diff --git a/modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache b/modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache
index 4a8a88e8750b..4f11ca1bf3c3 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache
@@ -2,40 +2,33 @@
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       {{#parent}}
       super(attributes)
       {{/parent}}
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/modules/openapi-generator/src/main/resources/ruby-client/partial_model_generic.mustache b/modules/openapi-generator/src/main/resources/ruby-client/partial_model_generic.mustache
index 8d0223f92f30..40745559b374 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/partial_model_generic.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/partial_model_generic.mustache
@@ -146,6 +146,12 @@
       else
         self.{{{name}}} = {{{defaultValue}}}
       {{/defaultValue}}
+      {{^defaultValue}}
+      {{#required}}
+      else
+        self.{{{name}}} = nil
+      {{/required}}
+      {{/defaultValue}}
       end
       {{/vars}}
     end
@@ -153,6 +159,7 @@
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = {{^parent}}Array.new{{/parent}}{{#parent}}super{{/parent}}
       {{#vars}}
       {{^isNullable}}
@@ -215,6 +222,7 @@
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       {{#vars}}
       {{^isNullable}}
       {{#required}}
@@ -291,52 +299,50 @@
     # @param [Object] {{{name}}} Value to be assigned
     def {{{name}}}=({{{name}}})
       {{^isNullable}}
-      {{#required}}
       if {{{name}}}.nil?
         fail ArgumentError, '{{{name}}} cannot be nil'
       end
 
-      {{/required}}
       {{/isNullable}}
       {{#maxLength}}
-      if {{^required}}!{{{name}}}.nil? && {{/required}}{{{name}}}.to_s.length > {{{maxLength}}}
+      if {{#isNullable}}!{{{name}}}.nil? && {{/isNullable}}{{{name}}}.to_s.length > {{{maxLength}}}
         fail ArgumentError, 'invalid value for "{{{name}}}", the character length must be smaller than or equal to {{{maxLength}}}.'
       end
 
       {{/maxLength}}
       {{#minLength}}
-      if {{^required}}!{{{name}}}.nil? && {{/required}}{{{name}}}.to_s.length < {{{minLength}}}
+      if {{#isNullable}}!{{{name}}}.nil? && {{/isNullable}}{{{name}}}.to_s.length < {{{minLength}}}
         fail ArgumentError, 'invalid value for "{{{name}}}", the character length must be great than or equal to {{{minLength}}}.'
       end
 
       {{/minLength}}
       {{#maximum}}
-      if {{^required}}!{{{name}}}.nil? && {{/required}}{{{name}}} >{{#exclusiveMaximum}}={{/exclusiveMaximum}} {{{maximum}}}
+      if {{#isNullable}}!{{{name}}}.nil? && {{/isNullable}}{{{name}}} >{{#exclusiveMaximum}}={{/exclusiveMaximum}} {{{maximum}}}
         fail ArgumentError, 'invalid value for "{{{name}}}", must be smaller than {{^exclusiveMaximum}}or equal to {{/exclusiveMaximum}}{{{maximum}}}.'
       end
 
       {{/maximum}}
       {{#minimum}}
-      if {{^required}}!{{{name}}}.nil? && {{/required}}{{{name}}} <{{#exclusiveMinimum}}={{/exclusiveMinimum}} {{{minimum}}}
+      if {{#isNullable}}!{{{name}}}.nil? && {{/isNullable}}{{{name}}} <{{#exclusiveMinimum}}={{/exclusiveMinimum}} {{{minimum}}}
         fail ArgumentError, 'invalid value for "{{{name}}}", must be greater than {{^exclusiveMinimum}}or equal to {{/exclusiveMinimum}}{{{minimum}}}.'
       end
 
       {{/minimum}}
       {{#pattern}}
       pattern = Regexp.new({{{pattern}}})
-      if {{^required}}!{{{name}}}.nil? && {{/required}}{{{name}}} !~ pattern
+      if {{#isNullable}}!{{{name}}}.nil? && {{/isNullable}}{{{name}}} !~ pattern
         fail ArgumentError, "invalid value for \"{{{name}}}\", must conform to the pattern #{pattern}."
       end
 
       {{/pattern}}
       {{#maxItems}}
-      if {{^required}}!{{{name}}}.nil? && {{/required}}{{{name}}}.length > {{{maxItems}}}
+      if {{#isNullable}}!{{{name}}}.nil? && {{/isNullable}}{{{name}}}.length > {{{maxItems}}}
         fail ArgumentError, 'invalid value for "{{{name}}}", number of items must be less than or equal to {{{maxItems}}}.'
       end
 
       {{/maxItems}}
       {{#minItems}}
-      if {{^required}}!{{{name}}}.nil? && {{/required}}{{{name}}}.length < {{{minItems}}}
+      if {{#isNullable}}!{{{name}}}.nil? && {{/isNullable}}{{{name}}}.length < {{{minItems}}}
         fail ArgumentError, 'invalid value for "{{{name}}}", number of items must be greater than or equal to {{{minItems}}}.'
       end
 
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/additional_properties_class.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/additional_properties_class.rb
index 09b4aa0f171e..5053f214ebd9 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/additional_properties_class.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/additional_properties_class.rb
@@ -77,6 +77,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -84,6 +85,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -112,37 +114,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/all_of_with_single_ref.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/all_of_with_single_ref.rb
index 7fa9cc1beace..e4292feed9b1 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/all_of_with_single_ref.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/all_of_with_single_ref.rb
@@ -95,6 +95,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -102,6 +103,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -130,37 +132,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/animal.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/animal.rb
index 14b080b79610..2c9ffb848e20 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/animal.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/animal.rb
@@ -68,6 +68,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'class_name')
         self.class_name = attributes[:'class_name']
+      else
+        self.class_name = nil
       end
 
       if attributes.key?(:'color')
@@ -80,6 +82,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @class_name.nil?
         invalid_properties.push('invalid value for "class_name", class_name cannot be nil.')
@@ -91,6 +94,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @class_name.nil?
       true
     end
@@ -120,37 +124,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/api_response.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/api_response.rb
index afe92b54ed45..bca30ec2f98c 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/api_response.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/api_response.rb
@@ -81,6 +81,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -88,6 +89,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -117,37 +119,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/array_of_array_of_number_only.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/array_of_array_of_number_only.rb
index 452252dcc840..cc634c871ed6 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/array_of_array_of_number_only.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/array_of_array_of_number_only.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/array_of_number_only.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/array_of_number_only.rb
index bcbd551ea327..1fd00c348554 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/array_of_number_only.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/array_of_number_only.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/array_test.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/array_test.rb
index 28f1f358b22e..85c62ba56aaa 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/array_test.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/array_test.rb
@@ -87,6 +87,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if !@array_of_string.nil? && @array_of_string.length > 3
         invalid_properties.push('invalid value for "array_of_string", number of items must be less than or equal to 3.')
@@ -102,6 +103,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if !@array_of_string.nil? && @array_of_string.length > 3
       return false if !@array_of_string.nil? && @array_of_string.length < 0
       true
@@ -110,11 +112,15 @@ def valid?
     # Custom attribute writer method with validation
     # @param [Object] array_of_string Value to be assigned
     def array_of_string=(array_of_string)
-      if !array_of_string.nil? && array_of_string.length > 3
+      if array_of_string.nil?
+        fail ArgumentError, 'array_of_string cannot be nil'
+      end
+
+      if array_of_string.length > 3
         fail ArgumentError, 'invalid value for "array_of_string", number of items must be less than or equal to 3.'
       end
 
-      if !array_of_string.nil? && array_of_string.length < 0
+      if array_of_string.length < 0
         fail ArgumentError, 'invalid value for "array_of_string", number of items must be greater than or equal to 0.'
       end
 
@@ -147,37 +153,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/capitalization.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/capitalization.rb
index a55b87091424..777b21148fc6 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/capitalization.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/capitalization.rb
@@ -106,6 +106,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -113,6 +114,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -145,37 +147,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/cat.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/cat.rb
index 59cc06ceae5e..4035fdd01b1a 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/cat.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/cat.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = super
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true && super
     end
 
@@ -109,38 +111,31 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/category.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/category.rb
index e38a0e24a103..4e5747b5b847 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/category.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/category.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -86,6 +87,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       true
     end
@@ -115,37 +117,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/class_model.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/class_model.rb
index 5a1ea761ff8e..6e8ecbd082e4 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/class_model.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/class_model.rb
@@ -66,6 +66,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -73,6 +74,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -100,37 +102,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/client.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/client.rb
index 28bcda26daad..e27237c4f988 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/client.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/client.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/deprecated_object.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/deprecated_object.rb
index 5cd8b8856a2c..8e5f4301b590 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/deprecated_object.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/deprecated_object.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/dog.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/dog.rb
index dbfac124513f..a290df6ccedf 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/dog.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/dog.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = super
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true && super
     end
 
@@ -109,38 +111,31 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/enum_arrays.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/enum_arrays.rb
index c42e545e081e..fbebf6fb5e89 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/enum_arrays.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/enum_arrays.rb
@@ -97,6 +97,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -104,6 +105,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       just_symbol_validator = EnumAttributeValidator.new('String', [">=", "$"])
       return false unless just_symbol_validator.valid?(@just_symbol)
       true
@@ -144,37 +146,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/enum_test.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/enum_test.rb
index 58c55ed401a3..f945ae59fd7b 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/enum_test.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/enum_test.rb
@@ -114,6 +114,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'enum_string_required')
         self.enum_string_required = attributes[:'enum_string_required']
+      else
+        self.enum_string_required = nil
       end
 
       if attributes.key?(:'enum_integer')
@@ -148,6 +150,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @enum_string_required.nil?
         invalid_properties.push('invalid value for "enum_string_required", enum_string_required cannot be nil.')
@@ -159,6 +162,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       enum_string_validator = EnumAttributeValidator.new('String', ["UPPER", "lower", ""])
       return false unless enum_string_validator.valid?(@enum_string)
       return false if @enum_string_required.nil?
@@ -242,37 +246,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/fake_big_decimal_map200_response.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/fake_big_decimal_map200_response.rb
index 9407b0f057b6..9a6c7ca46998 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/fake_big_decimal_map200_response.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/fake_big_decimal_map200_response.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -110,37 +112,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/file.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/file.rb
index 44bd87ec046e..4fbb52dcf440 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/file.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/file.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/file_schema_test_class.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/file_schema_test_class.rb
index 7c7b3d8a3248..2c208a9ef87e 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/file_schema_test_class.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/file_schema_test_class.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -110,37 +112,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/foo.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/foo.rb
index e6b03f67ee0f..71a64b7e4251 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/foo.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/foo.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/foo_get_default_response.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/foo_get_default_response.rb
index c32e9f721ca3..de7ebdc20a7d 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/foo_get_default_response.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/foo_get_default_response.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/format_test.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/format_test.rb
index 5d7bd35a9792..383ddcbcc9d1 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/format_test.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/format_test.rb
@@ -133,6 +133,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'number')
         self.number = attributes[:'number']
+      else
+        self.number = nil
       end
 
       if attributes.key?(:'float')
@@ -153,6 +155,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'byte')
         self.byte = attributes[:'byte']
+      else
+        self.byte = nil
       end
 
       if attributes.key?(:'binary')
@@ -161,6 +165,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'date')
         self.date = attributes[:'date']
+      else
+        self.date = nil
       end
 
       if attributes.key?(:'date_time')
@@ -173,6 +179,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'password')
         self.password = attributes[:'password']
+      else
+        self.password = nil
       end
 
       if attributes.key?(:'pattern_with_digits')
@@ -187,6 +195,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if !@integer.nil? && @integer > 100
         invalid_properties.push('invalid value for "integer", must be smaller than or equal to 100.')
@@ -273,6 +282,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if !@integer.nil? && @integer > 100
       return false if !@integer.nil? && @integer < 10
       return false if !@int32.nil? && @int32 > 200
@@ -298,11 +308,15 @@ def valid?
     # Custom attribute writer method with validation
     # @param [Object] integer Value to be assigned
     def integer=(integer)
-      if !integer.nil? && integer > 100
+      if integer.nil?
+        fail ArgumentError, 'integer cannot be nil'
+      end
+
+      if integer > 100
         fail ArgumentError, 'invalid value for "integer", must be smaller than or equal to 100.'
       end
 
-      if !integer.nil? && integer < 10
+      if integer < 10
         fail ArgumentError, 'invalid value for "integer", must be greater than or equal to 10.'
       end
 
@@ -312,11 +326,15 @@ def integer=(integer)
     # Custom attribute writer method with validation
     # @param [Object] int32 Value to be assigned
     def int32=(int32)
-      if !int32.nil? && int32 > 200
+      if int32.nil?
+        fail ArgumentError, 'int32 cannot be nil'
+      end
+
+      if int32 > 200
         fail ArgumentError, 'invalid value for "int32", must be smaller than or equal to 200.'
       end
 
-      if !int32.nil? && int32 < 20
+      if int32 < 20
         fail ArgumentError, 'invalid value for "int32", must be greater than or equal to 20.'
       end
 
@@ -344,11 +362,15 @@ def number=(number)
     # Custom attribute writer method with validation
     # @param [Object] float Value to be assigned
     def float=(float)
-      if !float.nil? && float > 987.6
+      if float.nil?
+        fail ArgumentError, 'float cannot be nil'
+      end
+
+      if float > 987.6
         fail ArgumentError, 'invalid value for "float", must be smaller than or equal to 987.6.'
       end
 
-      if !float.nil? && float < 54.3
+      if float < 54.3
         fail ArgumentError, 'invalid value for "float", must be greater than or equal to 54.3.'
       end
 
@@ -358,11 +380,15 @@ def float=(float)
     # Custom attribute writer method with validation
     # @param [Object] double Value to be assigned
     def double=(double)
-      if !double.nil? && double > 123.4
+      if double.nil?
+        fail ArgumentError, 'double cannot be nil'
+      end
+
+      if double > 123.4
         fail ArgumentError, 'invalid value for "double", must be smaller than or equal to 123.4.'
       end
 
-      if !double.nil? && double < 67.8
+      if double < 67.8
         fail ArgumentError, 'invalid value for "double", must be greater than or equal to 67.8.'
       end
 
@@ -372,8 +398,12 @@ def double=(double)
     # Custom attribute writer method with validation
     # @param [Object] string Value to be assigned
     def string=(string)
+      if string.nil?
+        fail ArgumentError, 'string cannot be nil'
+      end
+
       pattern = Regexp.new(/[a-z]/i)
-      if !string.nil? && string !~ pattern
+      if string !~ pattern
         fail ArgumentError, "invalid value for \"string\", must conform to the pattern #{pattern}."
       end
 
@@ -401,8 +431,12 @@ def password=(password)
     # Custom attribute writer method with validation
     # @param [Object] pattern_with_digits Value to be assigned
     def pattern_with_digits=(pattern_with_digits)
+      if pattern_with_digits.nil?
+        fail ArgumentError, 'pattern_with_digits cannot be nil'
+      end
+
       pattern = Regexp.new(/^\d{10}$/)
-      if !pattern_with_digits.nil? && pattern_with_digits !~ pattern
+      if pattern_with_digits !~ pattern
         fail ArgumentError, "invalid value for \"pattern_with_digits\", must conform to the pattern #{pattern}."
       end
 
@@ -412,8 +446,12 @@ def pattern_with_digits=(pattern_with_digits)
     # Custom attribute writer method with validation
     # @param [Object] pattern_with_digits_and_delimiter Value to be assigned
     def pattern_with_digits_and_delimiter=(pattern_with_digits_and_delimiter)
+      if pattern_with_digits_and_delimiter.nil?
+        fail ArgumentError, 'pattern_with_digits_and_delimiter cannot be nil'
+      end
+
       pattern = Regexp.new(/^image_\d{1,3}$/i)
-      if !pattern_with_digits_and_delimiter.nil? && pattern_with_digits_and_delimiter !~ pattern
+      if pattern_with_digits_and_delimiter !~ pattern
         fail ArgumentError, "invalid value for \"pattern_with_digits_and_delimiter\", must conform to the pattern #{pattern}."
       end
 
@@ -459,37 +497,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/has_only_read_only.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/has_only_read_only.rb
index df54b67cf987..b22799315a3a 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/has_only_read_only.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/has_only_read_only.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/health_check_result.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/health_check_result.rb
index 12845874f8d7..ef7ee79d79f1 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/health_check_result.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/health_check_result.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/list.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/list.rb
index 32065095d9e0..2c0fbf10831d 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/list.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/list.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/map_test.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/map_test.rb
index 181c1c991a14..2f0b4b6aefba 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/map_test.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/map_test.rb
@@ -119,6 +119,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -126,6 +127,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -156,37 +158,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/mixed_properties_and_additional_properties_class.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
index 93a1c6c4d747..93cb35097c02 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
@@ -83,6 +83,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -90,6 +91,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -119,37 +121,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/model200_response.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/model200_response.rb
index 9dd11b88dcc8..c857b893607a 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/model200_response.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/model200_response.rb
@@ -74,6 +74,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -81,6 +82,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -109,37 +111,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/model_return.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/model_return.rb
index 1543f71d5ddb..3580c74908d1 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/model_return.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/model_return.rb
@@ -66,6 +66,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -73,6 +74,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -100,37 +102,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/name.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/name.rb
index e0f4d00c0b5b..befba0746d3c 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/name.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/name.rb
@@ -72,6 +72,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'name')
         self.name = attributes[:'name']
+      else
+        self.name = nil
       end
 
       if attributes.key?(:'snake_case')
@@ -90,6 +92,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -101,6 +104,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       true
     end
@@ -132,37 +136,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/nullable_class.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/nullable_class.rb
index cc768c1a03a6..efbd3bd5fe60 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/nullable_class.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/nullable_class.rb
@@ -175,6 +175,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -182,6 +183,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -220,37 +222,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/number_only.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/number_only.rb
index b04314c703cf..ac3b7457f513 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/number_only.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/number_only.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/object_with_deprecated_fields.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/object_with_deprecated_fields.rb
index 8f511458c6df..9f6558d0a2cf 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/object_with_deprecated_fields.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/object_with_deprecated_fields.rb
@@ -91,6 +91,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -98,6 +99,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -128,37 +130,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/order.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/order.rb
index 9ab55bee6164..e57d1f39f0bf 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/order.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/order.rb
@@ -130,6 +130,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -137,6 +138,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       status_validator = EnumAttributeValidator.new('String', ["placed", "approved", "delivered"])
       return false unless status_validator.valid?(@status)
       true
@@ -181,37 +183,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/outer_composite.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/outer_composite.rb
index ba83c2a5008f..0e6ec4c25c86 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/outer_composite.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/outer_composite.rb
@@ -81,6 +81,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -88,6 +89,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -117,37 +119,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/outer_object_with_enum_property.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/outer_object_with_enum_property.rb
index 4bd272ff2b9e..f2b04477e131 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/outer_object_with_enum_property.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/outer_object_with_enum_property.rb
@@ -81,12 +81,15 @@ def initialize(attributes = {})
 
       if attributes.key?(:'value')
         self.value = attributes[:'value']
+      else
+        self.value = nil
       end
     end
 
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @value.nil?
         invalid_properties.push('invalid value for "value", value cannot be nil.')
@@ -98,6 +101,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @value.nil?
       true
     end
@@ -126,37 +130,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/pet.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/pet.rb
index 78934ccb0301..f71fbd02617f 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/pet.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/pet.rb
@@ -110,12 +110,16 @@ def initialize(attributes = {})
 
       if attributes.key?(:'name')
         self.name = attributes[:'name']
+      else
+        self.name = nil
       end
 
       if attributes.key?(:'photo_urls')
         if (value = attributes[:'photo_urls']).is_a?(Array)
           self.photo_urls = value
         end
+      else
+        self.photo_urls = nil
       end
 
       if attributes.key?(:'tags')
@@ -132,6 +136,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -147,6 +152,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       return false if @photo_urls.nil?
       status_validator = EnumAttributeValidator.new('String', ["available", "pending", "sold"])
@@ -203,37 +209,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/read_only_first.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/read_only_first.rb
index 8afb713ede88..359bd8fc9b54 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/read_only_first.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/read_only_first.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/special_model_name.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/special_model_name.rb
index d1a049eec39f..250e980e6940 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/special_model_name.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/special_model_name.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/tag.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/tag.rb
index 894e4c24acc3..e81f82c3927b 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/tag.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/tag.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/models/user.rb b/samples/client/petstore/ruby-autoload/lib/petstore/models/user.rb
index e34d1381ea41..a25dd1cd5b3d 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/models/user.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/models/user.rb
@@ -122,6 +122,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -129,6 +130,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -163,37 +165,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-autoload/spec/models/format_test_spec.rb b/samples/client/petstore/ruby-autoload/spec/models/format_test_spec.rb
index f1c2847da938..4ed014c36174 100644
--- a/samples/client/petstore/ruby-autoload/spec/models/format_test_spec.rb
+++ b/samples/client/petstore/ruby-autoload/spec/models/format_test_spec.rb
@@ -18,7 +18,12 @@
 # Automatically generated by openapi-generator (https://openapi-generator.tech)
 # Please update as you see appropriate
 describe Petstore::FormatTest do
-  let(:instance) { Petstore::FormatTest.new }
+  let(:instance) { Petstore::FormatTest.new({
+    number: 65,
+    byte: '1234356',
+    date: Date.parse('2007-12-03T10:15:30+01:00'),
+    password: 'password123'
+  }) }
 
   describe 'test an instance of FormatTest' do
     it 'should create an instance of FormatTest' do
diff --git a/samples/client/petstore/ruby-autoload/spec/models/pet_spec.rb b/samples/client/petstore/ruby-autoload/spec/models/pet_spec.rb
index 930130c85c42..6f7a9f9df7bd 100644
--- a/samples/client/petstore/ruby-autoload/spec/models/pet_spec.rb
+++ b/samples/client/petstore/ruby-autoload/spec/models/pet_spec.rb
@@ -18,7 +18,7 @@
 # Automatically generated by openapi-generator (https://openapi-generator.tech)
 # Please update as you see appropriate
 describe Petstore::Pet do
-  let(:instance) { Petstore::Pet.new }
+  let(:instance) { Petstore::Pet.new({ name: 'Kitty', photo_urls: ['www.photo-url.test'] }) }
 
   describe 'test an instance of Pet' do
     it 'should create an instance of Pet' do
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb
index 09b4aa0f171e..5053f214ebd9 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb
@@ -77,6 +77,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -84,6 +85,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -112,37 +114,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/all_of_with_single_ref.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/all_of_with_single_ref.rb
index 7fa9cc1beace..e4292feed9b1 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/all_of_with_single_ref.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/all_of_with_single_ref.rb
@@ -95,6 +95,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -102,6 +103,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -130,37 +132,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb
index 14b080b79610..2c9ffb848e20 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb
@@ -68,6 +68,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'class_name')
         self.class_name = attributes[:'class_name']
+      else
+        self.class_name = nil
       end
 
       if attributes.key?(:'color')
@@ -80,6 +82,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @class_name.nil?
         invalid_properties.push('invalid value for "class_name", class_name cannot be nil.')
@@ -91,6 +94,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @class_name.nil?
       true
     end
@@ -120,37 +124,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb
index afe92b54ed45..bca30ec2f98c 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb
@@ -81,6 +81,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -88,6 +89,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -117,37 +119,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb
index 452252dcc840..cc634c871ed6 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb
index bcbd551ea327..1fd00c348554 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb
index 28f1f358b22e..85c62ba56aaa 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb
@@ -87,6 +87,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if !@array_of_string.nil? && @array_of_string.length > 3
         invalid_properties.push('invalid value for "array_of_string", number of items must be less than or equal to 3.')
@@ -102,6 +103,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if !@array_of_string.nil? && @array_of_string.length > 3
       return false if !@array_of_string.nil? && @array_of_string.length < 0
       true
@@ -110,11 +112,15 @@ def valid?
     # Custom attribute writer method with validation
     # @param [Object] array_of_string Value to be assigned
     def array_of_string=(array_of_string)
-      if !array_of_string.nil? && array_of_string.length > 3
+      if array_of_string.nil?
+        fail ArgumentError, 'array_of_string cannot be nil'
+      end
+
+      if array_of_string.length > 3
         fail ArgumentError, 'invalid value for "array_of_string", number of items must be less than or equal to 3.'
       end
 
-      if !array_of_string.nil? && array_of_string.length < 0
+      if array_of_string.length < 0
         fail ArgumentError, 'invalid value for "array_of_string", number of items must be greater than or equal to 0.'
       end
 
@@ -147,37 +153,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb
index a55b87091424..777b21148fc6 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb
@@ -106,6 +106,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -113,6 +114,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -145,37 +147,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb
index 59cc06ceae5e..4035fdd01b1a 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = super
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true && super
     end
 
@@ -109,38 +111,31 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb
index e38a0e24a103..4e5747b5b847 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -86,6 +87,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       true
     end
@@ -115,37 +117,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb
index 5a1ea761ff8e..6e8ecbd082e4 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb
@@ -66,6 +66,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -73,6 +74,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -100,37 +102,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb
index 28bcda26daad..e27237c4f988 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/deprecated_object.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/deprecated_object.rb
index 5cd8b8856a2c..8e5f4301b590 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/deprecated_object.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/deprecated_object.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb
index dbfac124513f..a290df6ccedf 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = super
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true && super
     end
 
@@ -109,38 +111,31 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb
index c42e545e081e..fbebf6fb5e89 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb
@@ -97,6 +97,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -104,6 +105,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       just_symbol_validator = EnumAttributeValidator.new('String', [">=", "$"])
       return false unless just_symbol_validator.valid?(@just_symbol)
       true
@@ -144,37 +146,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb
index 58c55ed401a3..f945ae59fd7b 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb
@@ -114,6 +114,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'enum_string_required')
         self.enum_string_required = attributes[:'enum_string_required']
+      else
+        self.enum_string_required = nil
       end
 
       if attributes.key?(:'enum_integer')
@@ -148,6 +150,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @enum_string_required.nil?
         invalid_properties.push('invalid value for "enum_string_required", enum_string_required cannot be nil.')
@@ -159,6 +162,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       enum_string_validator = EnumAttributeValidator.new('String', ["UPPER", "lower", ""])
       return false unless enum_string_validator.valid?(@enum_string)
       return false if @enum_string_required.nil?
@@ -242,37 +246,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/fake_big_decimal_map200_response.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/fake_big_decimal_map200_response.rb
index 9407b0f057b6..9a6c7ca46998 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/fake_big_decimal_map200_response.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/fake_big_decimal_map200_response.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -110,37 +112,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb
index 44bd87ec046e..4fbb52dcf440 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb
index 7c7b3d8a3248..2c208a9ef87e 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -110,37 +112,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/foo.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/foo.rb
index e6b03f67ee0f..71a64b7e4251 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/foo.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/foo.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/foo_get_default_response.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/foo_get_default_response.rb
index c32e9f721ca3..de7ebdc20a7d 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/foo_get_default_response.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/foo_get_default_response.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb
index 5d7bd35a9792..383ddcbcc9d1 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb
@@ -133,6 +133,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'number')
         self.number = attributes[:'number']
+      else
+        self.number = nil
       end
 
       if attributes.key?(:'float')
@@ -153,6 +155,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'byte')
         self.byte = attributes[:'byte']
+      else
+        self.byte = nil
       end
 
       if attributes.key?(:'binary')
@@ -161,6 +165,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'date')
         self.date = attributes[:'date']
+      else
+        self.date = nil
       end
 
       if attributes.key?(:'date_time')
@@ -173,6 +179,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'password')
         self.password = attributes[:'password']
+      else
+        self.password = nil
       end
 
       if attributes.key?(:'pattern_with_digits')
@@ -187,6 +195,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if !@integer.nil? && @integer > 100
         invalid_properties.push('invalid value for "integer", must be smaller than or equal to 100.')
@@ -273,6 +282,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if !@integer.nil? && @integer > 100
       return false if !@integer.nil? && @integer < 10
       return false if !@int32.nil? && @int32 > 200
@@ -298,11 +308,15 @@ def valid?
     # Custom attribute writer method with validation
     # @param [Object] integer Value to be assigned
     def integer=(integer)
-      if !integer.nil? && integer > 100
+      if integer.nil?
+        fail ArgumentError, 'integer cannot be nil'
+      end
+
+      if integer > 100
         fail ArgumentError, 'invalid value for "integer", must be smaller than or equal to 100.'
       end
 
-      if !integer.nil? && integer < 10
+      if integer < 10
         fail ArgumentError, 'invalid value for "integer", must be greater than or equal to 10.'
       end
 
@@ -312,11 +326,15 @@ def integer=(integer)
     # Custom attribute writer method with validation
     # @param [Object] int32 Value to be assigned
     def int32=(int32)
-      if !int32.nil? && int32 > 200
+      if int32.nil?
+        fail ArgumentError, 'int32 cannot be nil'
+      end
+
+      if int32 > 200
         fail ArgumentError, 'invalid value for "int32", must be smaller than or equal to 200.'
       end
 
-      if !int32.nil? && int32 < 20
+      if int32 < 20
         fail ArgumentError, 'invalid value for "int32", must be greater than or equal to 20.'
       end
 
@@ -344,11 +362,15 @@ def number=(number)
     # Custom attribute writer method with validation
     # @param [Object] float Value to be assigned
     def float=(float)
-      if !float.nil? && float > 987.6
+      if float.nil?
+        fail ArgumentError, 'float cannot be nil'
+      end
+
+      if float > 987.6
         fail ArgumentError, 'invalid value for "float", must be smaller than or equal to 987.6.'
       end
 
-      if !float.nil? && float < 54.3
+      if float < 54.3
         fail ArgumentError, 'invalid value for "float", must be greater than or equal to 54.3.'
       end
 
@@ -358,11 +380,15 @@ def float=(float)
     # Custom attribute writer method with validation
     # @param [Object] double Value to be assigned
     def double=(double)
-      if !double.nil? && double > 123.4
+      if double.nil?
+        fail ArgumentError, 'double cannot be nil'
+      end
+
+      if double > 123.4
         fail ArgumentError, 'invalid value for "double", must be smaller than or equal to 123.4.'
       end
 
-      if !double.nil? && double < 67.8
+      if double < 67.8
         fail ArgumentError, 'invalid value for "double", must be greater than or equal to 67.8.'
       end
 
@@ -372,8 +398,12 @@ def double=(double)
     # Custom attribute writer method with validation
     # @param [Object] string Value to be assigned
     def string=(string)
+      if string.nil?
+        fail ArgumentError, 'string cannot be nil'
+      end
+
       pattern = Regexp.new(/[a-z]/i)
-      if !string.nil? && string !~ pattern
+      if string !~ pattern
         fail ArgumentError, "invalid value for \"string\", must conform to the pattern #{pattern}."
       end
 
@@ -401,8 +431,12 @@ def password=(password)
     # Custom attribute writer method with validation
     # @param [Object] pattern_with_digits Value to be assigned
     def pattern_with_digits=(pattern_with_digits)
+      if pattern_with_digits.nil?
+        fail ArgumentError, 'pattern_with_digits cannot be nil'
+      end
+
       pattern = Regexp.new(/^\d{10}$/)
-      if !pattern_with_digits.nil? && pattern_with_digits !~ pattern
+      if pattern_with_digits !~ pattern
         fail ArgumentError, "invalid value for \"pattern_with_digits\", must conform to the pattern #{pattern}."
       end
 
@@ -412,8 +446,12 @@ def pattern_with_digits=(pattern_with_digits)
     # Custom attribute writer method with validation
     # @param [Object] pattern_with_digits_and_delimiter Value to be assigned
     def pattern_with_digits_and_delimiter=(pattern_with_digits_and_delimiter)
+      if pattern_with_digits_and_delimiter.nil?
+        fail ArgumentError, 'pattern_with_digits_and_delimiter cannot be nil'
+      end
+
       pattern = Regexp.new(/^image_\d{1,3}$/i)
-      if !pattern_with_digits_and_delimiter.nil? && pattern_with_digits_and_delimiter !~ pattern
+      if pattern_with_digits_and_delimiter !~ pattern
         fail ArgumentError, "invalid value for \"pattern_with_digits_and_delimiter\", must conform to the pattern #{pattern}."
       end
 
@@ -459,37 +497,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb
index df54b67cf987..b22799315a3a 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/health_check_result.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/health_check_result.rb
index 12845874f8d7..ef7ee79d79f1 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/health_check_result.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/health_check_result.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb
index 32065095d9e0..2c0fbf10831d 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb
index 181c1c991a14..2f0b4b6aefba 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb
@@ -119,6 +119,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -126,6 +127,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -156,37 +158,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
index 93a1c6c4d747..93cb35097c02 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
@@ -83,6 +83,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -90,6 +91,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -119,37 +121,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb
index 9dd11b88dcc8..c857b893607a 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb
@@ -74,6 +74,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -81,6 +82,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -109,37 +111,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb
index 1543f71d5ddb..3580c74908d1 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb
@@ -66,6 +66,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -73,6 +74,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -100,37 +102,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb
index e0f4d00c0b5b..befba0746d3c 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb
@@ -72,6 +72,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'name')
         self.name = attributes[:'name']
+      else
+        self.name = nil
       end
 
       if attributes.key?(:'snake_case')
@@ -90,6 +92,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -101,6 +104,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       true
     end
@@ -132,37 +136,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/nullable_class.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/nullable_class.rb
index cc768c1a03a6..efbd3bd5fe60 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/nullable_class.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/nullable_class.rb
@@ -175,6 +175,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -182,6 +183,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -220,37 +222,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb
index b04314c703cf..ac3b7457f513 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/object_with_deprecated_fields.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/object_with_deprecated_fields.rb
index 8f511458c6df..9f6558d0a2cf 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/object_with_deprecated_fields.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/object_with_deprecated_fields.rb
@@ -91,6 +91,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -98,6 +99,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -128,37 +130,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb
index 9ab55bee6164..e57d1f39f0bf 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb
@@ -130,6 +130,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -137,6 +138,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       status_validator = EnumAttributeValidator.new('String', ["placed", "approved", "delivered"])
       return false unless status_validator.valid?(@status)
       true
@@ -181,37 +183,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb
index ba83c2a5008f..0e6ec4c25c86 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb
@@ -81,6 +81,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -88,6 +89,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -117,37 +119,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_object_with_enum_property.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_object_with_enum_property.rb
index 4bd272ff2b9e..f2b04477e131 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_object_with_enum_property.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_object_with_enum_property.rb
@@ -81,12 +81,15 @@ def initialize(attributes = {})
 
       if attributes.key?(:'value')
         self.value = attributes[:'value']
+      else
+        self.value = nil
       end
     end
 
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @value.nil?
         invalid_properties.push('invalid value for "value", value cannot be nil.')
@@ -98,6 +101,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @value.nil?
       true
     end
@@ -126,37 +130,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb
index 78934ccb0301..f71fbd02617f 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb
@@ -110,12 +110,16 @@ def initialize(attributes = {})
 
       if attributes.key?(:'name')
         self.name = attributes[:'name']
+      else
+        self.name = nil
       end
 
       if attributes.key?(:'photo_urls')
         if (value = attributes[:'photo_urls']).is_a?(Array)
           self.photo_urls = value
         end
+      else
+        self.photo_urls = nil
       end
 
       if attributes.key?(:'tags')
@@ -132,6 +136,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -147,6 +152,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       return false if @photo_urls.nil?
       status_validator = EnumAttributeValidator.new('String', ["available", "pending", "sold"])
@@ -203,37 +209,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb
index 8afb713ede88..359bd8fc9b54 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb
index d1a049eec39f..250e980e6940 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb
index 894e4c24acc3..e81f82c3927b 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb
index e34d1381ea41..a25dd1cd5b3d 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb
@@ -122,6 +122,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -129,6 +130,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -163,37 +165,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby-faraday/spec/custom/base_object_spec.rb b/samples/client/petstore/ruby-faraday/spec/custom/base_object_spec.rb
index a603b6d3c442..15e27c6e3b08 100644
--- a/samples/client/petstore/ruby-faraday/spec/custom/base_object_spec.rb
+++ b/samples/client/petstore/ruby-faraday/spec/custom/base_object_spec.rb
@@ -28,6 +28,68 @@ def self.openapi_types
       :boolean_false_arr => :'Array<Boolean>',
     }
   end
+
+  def initialize(attributes = {})
+    if (!attributes.is_a?(Hash))
+      fail ArgumentError, "The input argument (attributes) must be a hash in `ArrayMapObject` initialize method"
+    end
+
+    # check to see if the attribute exists and convert string to symbol for hash key
+    attributes = attributes.each_with_object({}) { |(k, v), h|
+      if (!self.class.attribute_map.key?(k.to_sym))
+        fail ArgumentError, "`#{k}` is not a valid attribute in `ArrayMapObject`. Please check the name to make sure it's valid. List of attributes: " + self.class.attribute_map.keys.inspect
+      end
+      h[k.to_sym] = v
+    }
+
+    if attributes.key?(:'int_arr')
+      if (value = attributes[:'int_arr']).is_a?(Array)
+        self.int_arr = value
+      end
+    end
+
+    if attributes.key?(:'pet_arr')
+      if (value = attributes[:'pet_arr']).is_a?(Array)
+        self.pet_arr = value
+      end
+    end
+
+    if attributes.key?(:'int_map')
+      if (value = attributes[:'int_map']).is_a?(Hash)
+        self.int_map = value
+      end
+    end
+
+    if attributes.key?(:'pet_map')
+      if (value = attributes[:'pet_map']).is_a?(Hash)
+        self.pet_map = value
+      end
+    end
+
+    if attributes.key?(:'int_arr_map')
+      if (value = attributes[:'int_arr_map']).is_a?(Hash)
+        self.int_arr_map = value
+      end
+    end
+
+    if attributes.key?(:'pet_arr_map')
+      if (value = attributes[:'pet_arr_map']).is_a?(Hash)
+        self.pet_arr_map = value
+      end
+    end
+
+    if attributes.key?(:'boolean_true_arr')
+      if (value = attributes[:'boolean_true_arr']).is_a?(Array)
+        self.boolean_true_arr = value
+      end
+    end
+
+    if attributes.key?(:'boolean_false_arr')
+      if (value = attributes[:'boolean_false_arr']).is_a?(Array)
+        self.boolean_false_arr = value
+      end
+    end
+  end
 end
 
 describe 'BaseObject' do
@@ -41,22 +103,20 @@ def self.openapi_types
   end
 
   describe 'array and map properties' do
-    let(:obj) { ArrayMapObject.new }
-
     let(:data) do
       { int_arr: [123, 456],
-       pet_arr: [{ name: 'Kitty' }],
+       pet_arr: [{ name: 'Kitty', photoUrls: ['www.photo-url.test'] }],
        int_map: { 'int' => 123 },
-       pet_map: { 'pet' => { name: 'Kitty' } },
+       pet_map: { 'pet' => { name: 'Kitty', photoUrls: ['www.photo-url.test'] } },
        int_arr_map: { 'int_arr' => [123, 456] },
-       pet_arr_map: { 'pet_arr' => [{ name: 'Kitty' }] },
+       pet_arr_map: { 'pet_arr' => [{ name: 'Kitty', photoUrls: ['www.photo-url.test'] }] },
        boolean_true_arr:  [true, "true", "TruE", 1, "y", "yes", "1", "t", "T"],
        boolean_false_arr: [false, "", 0, "0", "f", nil, "null", "\ntrue\n"],
       }
     end
 
     it 'works for #build_from_hash' do
-      obj.build_from_hash(data)
+      obj = ArrayMapObject.build_from_hash(data)
 
       expect(obj.int_arr).to match_array([123, 456])
 
@@ -99,7 +159,7 @@ def self.openapi_types
     end
 
     it 'works for #to_hash' do
-      obj.build_from_hash(data)
+      obj = ArrayMapObject.build_from_hash(data)
       expect_data = data.dup
       expect_data[:boolean_true_arr].map! { true }
       expect_data[:boolean_false_arr].map! { false }
diff --git a/samples/client/petstore/ruby-faraday/spec/custom/pet_spec.rb b/samples/client/petstore/ruby-faraday/spec/custom/pet_spec.rb
index 8b2baf8ba5f2..1fbec557bee4 100644
--- a/samples/client/petstore/ruby-faraday/spec/custom/pet_spec.rb
+++ b/samples/client/petstore/ruby-faraday/spec/custom/pet_spec.rb
@@ -42,8 +42,7 @@
       expect(pet.category.name).to eq('category unknown')
 
       # test build_from_hash
-      pet2 = Petstore::Pet.new
-      pet2.build_from_hash(pet.to_hash)
+      pet2 = Petstore::Pet.build_from_hash(pet.to_hash)
       expect(pet.to_hash).to eq(pet2.to_hash)
 
       # make sure sub-object has different object id
@@ -157,7 +156,7 @@
     it "should create a pet" do
       id = @pet_id + 1
 
-      pet = Petstore::Pet.new('id' => id, 'name' => "RUBY UNIT TESTING")
+      pet = Petstore::Pet.new('id' => id, 'name' => "RUBY UNIT TESTING", 'photo_urls' => ['www.photo-url.test'])
       result = @pet_api.add_pet(pet)
       # nothing is returned
       expect(result).to be_nil
@@ -165,6 +164,7 @@
       pet = @pet_api.get_pet_by_id(id)
       expect(pet.id).to eq(id)
       expect(pet.name).to eq("RUBY UNIT TESTING")
+      expect(pet.photo_urls).to match_array(['www.photo-url.test'])
 
       @pet_api.delete_pet(id)
     end
@@ -182,8 +182,12 @@
     end
 
     it "should implement eql? and hash" do
-      pet1 = Petstore::Pet.new
-      pet2 = Petstore::Pet.new
+      pet_hash = {
+        name: 'test_name',
+        photo_urls: ['www.photo-url.test']
+      }
+      pet1 = Petstore::Pet.new(pet_hash)
+      pet2 = Petstore::Pet.new(pet_hash)
       expect(pet1).to eq(pet2)
       expect(pet2).to eq(pet1)
       expect(pet1.eql?(pet2)).to eq(true)
diff --git a/samples/client/petstore/ruby-faraday/spec/models/format_test_spec.rb b/samples/client/petstore/ruby-faraday/spec/models/format_test_spec.rb
index a2cda082f02f..c6408011fbc5 100644
--- a/samples/client/petstore/ruby-faraday/spec/models/format_test_spec.rb
+++ b/samples/client/petstore/ruby-faraday/spec/models/format_test_spec.rb
@@ -20,7 +20,12 @@
 describe 'FormatTest' do
   before do
     # run before each test
-    @instance = Petstore::FormatTest.new
+    @instance = Petstore::FormatTest.new({
+      number: 65,
+      byte: '1234356',
+      date: Date.parse('2007-12-03T10:15:30+01:00'),
+      password: 'password123'
+    })
   end
 
   after do
diff --git a/samples/client/petstore/ruby-faraday/spec/models/pet_spec.rb b/samples/client/petstore/ruby-faraday/spec/models/pet_spec.rb
index f8a46865240f..08a4e8f61c98 100644
--- a/samples/client/petstore/ruby-faraday/spec/models/pet_spec.rb
+++ b/samples/client/petstore/ruby-faraday/spec/models/pet_spec.rb
@@ -20,7 +20,7 @@
 describe 'Pet' do
   before do
     # run before each test
-    @instance = Petstore::Pet.new
+    @instance = Petstore::Pet.new({ name: 'Kitty', photo_urls: ['www.photo-url.test'] })
   end
 
   after do
diff --git a/samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb b/samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb
index 09b4aa0f171e..5053f214ebd9 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb
@@ -77,6 +77,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -84,6 +85,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -112,37 +114,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/all_of_with_single_ref.rb b/samples/client/petstore/ruby/lib/petstore/models/all_of_with_single_ref.rb
index 7fa9cc1beace..e4292feed9b1 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/all_of_with_single_ref.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/all_of_with_single_ref.rb
@@ -95,6 +95,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -102,6 +103,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -130,37 +132,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/animal.rb b/samples/client/petstore/ruby/lib/petstore/models/animal.rb
index 14b080b79610..2c9ffb848e20 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/animal.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/animal.rb
@@ -68,6 +68,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'class_name')
         self.class_name = attributes[:'class_name']
+      else
+        self.class_name = nil
       end
 
       if attributes.key?(:'color')
@@ -80,6 +82,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @class_name.nil?
         invalid_properties.push('invalid value for "class_name", class_name cannot be nil.')
@@ -91,6 +94,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @class_name.nil?
       true
     end
@@ -120,37 +124,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/api_response.rb b/samples/client/petstore/ruby/lib/petstore/models/api_response.rb
index afe92b54ed45..bca30ec2f98c 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/api_response.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/api_response.rb
@@ -81,6 +81,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -88,6 +89,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -117,37 +119,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb b/samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb
index 452252dcc840..cc634c871ed6 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb b/samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb
index bcbd551ea327..1fd00c348554 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/array_test.rb b/samples/client/petstore/ruby/lib/petstore/models/array_test.rb
index 28f1f358b22e..85c62ba56aaa 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/array_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/array_test.rb
@@ -87,6 +87,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if !@array_of_string.nil? && @array_of_string.length > 3
         invalid_properties.push('invalid value for "array_of_string", number of items must be less than or equal to 3.')
@@ -102,6 +103,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if !@array_of_string.nil? && @array_of_string.length > 3
       return false if !@array_of_string.nil? && @array_of_string.length < 0
       true
@@ -110,11 +112,15 @@ def valid?
     # Custom attribute writer method with validation
     # @param [Object] array_of_string Value to be assigned
     def array_of_string=(array_of_string)
-      if !array_of_string.nil? && array_of_string.length > 3
+      if array_of_string.nil?
+        fail ArgumentError, 'array_of_string cannot be nil'
+      end
+
+      if array_of_string.length > 3
         fail ArgumentError, 'invalid value for "array_of_string", number of items must be less than or equal to 3.'
       end
 
-      if !array_of_string.nil? && array_of_string.length < 0
+      if array_of_string.length < 0
         fail ArgumentError, 'invalid value for "array_of_string", number of items must be greater than or equal to 0.'
       end
 
@@ -147,37 +153,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/capitalization.rb b/samples/client/petstore/ruby/lib/petstore/models/capitalization.rb
index a55b87091424..777b21148fc6 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/capitalization.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/capitalization.rb
@@ -106,6 +106,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -113,6 +114,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -145,37 +147,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/cat.rb b/samples/client/petstore/ruby/lib/petstore/models/cat.rb
index 59cc06ceae5e..4035fdd01b1a 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/cat.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/cat.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = super
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true && super
     end
 
@@ -109,38 +111,31 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/category.rb b/samples/client/petstore/ruby/lib/petstore/models/category.rb
index e38a0e24a103..4e5747b5b847 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/category.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/category.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -86,6 +87,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       true
     end
@@ -115,37 +117,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/class_model.rb b/samples/client/petstore/ruby/lib/petstore/models/class_model.rb
index 5a1ea761ff8e..6e8ecbd082e4 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/class_model.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/class_model.rb
@@ -66,6 +66,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -73,6 +74,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -100,37 +102,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/client.rb b/samples/client/petstore/ruby/lib/petstore/models/client.rb
index 28bcda26daad..e27237c4f988 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/client.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/client.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/deprecated_object.rb b/samples/client/petstore/ruby/lib/petstore/models/deprecated_object.rb
index 5cd8b8856a2c..8e5f4301b590 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/deprecated_object.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/deprecated_object.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/dog.rb b/samples/client/petstore/ruby/lib/petstore/models/dog.rb
index dbfac124513f..a290df6ccedf 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/dog.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/dog.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = super
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true && super
     end
 
@@ -109,38 +111,31 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb b/samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb
index c42e545e081e..fbebf6fb5e89 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb
@@ -97,6 +97,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -104,6 +105,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       just_symbol_validator = EnumAttributeValidator.new('String', [">=", "$"])
       return false unless just_symbol_validator.valid?(@just_symbol)
       true
@@ -144,37 +146,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/enum_test.rb b/samples/client/petstore/ruby/lib/petstore/models/enum_test.rb
index 58c55ed401a3..f945ae59fd7b 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/enum_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/enum_test.rb
@@ -114,6 +114,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'enum_string_required')
         self.enum_string_required = attributes[:'enum_string_required']
+      else
+        self.enum_string_required = nil
       end
 
       if attributes.key?(:'enum_integer')
@@ -148,6 +150,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @enum_string_required.nil?
         invalid_properties.push('invalid value for "enum_string_required", enum_string_required cannot be nil.')
@@ -159,6 +162,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       enum_string_validator = EnumAttributeValidator.new('String', ["UPPER", "lower", ""])
       return false unless enum_string_validator.valid?(@enum_string)
       return false if @enum_string_required.nil?
@@ -242,37 +246,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/fake_big_decimal_map200_response.rb b/samples/client/petstore/ruby/lib/petstore/models/fake_big_decimal_map200_response.rb
index 9407b0f057b6..9a6c7ca46998 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/fake_big_decimal_map200_response.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/fake_big_decimal_map200_response.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -110,37 +112,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/file.rb b/samples/client/petstore/ruby/lib/petstore/models/file.rb
index 44bd87ec046e..4fbb52dcf440 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/file.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/file.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb b/samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb
index 7c7b3d8a3248..2c208a9ef87e 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb
@@ -75,6 +75,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -82,6 +83,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -110,37 +112,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/foo.rb b/samples/client/petstore/ruby/lib/petstore/models/foo.rb
index e6b03f67ee0f..71a64b7e4251 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/foo.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/foo.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/foo_get_default_response.rb b/samples/client/petstore/ruby/lib/petstore/models/foo_get_default_response.rb
index c32e9f721ca3..de7ebdc20a7d 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/foo_get_default_response.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/foo_get_default_response.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/format_test.rb b/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
index 5d7bd35a9792..383ddcbcc9d1 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
@@ -133,6 +133,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'number')
         self.number = attributes[:'number']
+      else
+        self.number = nil
       end
 
       if attributes.key?(:'float')
@@ -153,6 +155,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'byte')
         self.byte = attributes[:'byte']
+      else
+        self.byte = nil
       end
 
       if attributes.key?(:'binary')
@@ -161,6 +165,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'date')
         self.date = attributes[:'date']
+      else
+        self.date = nil
       end
 
       if attributes.key?(:'date_time')
@@ -173,6 +179,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'password')
         self.password = attributes[:'password']
+      else
+        self.password = nil
       end
 
       if attributes.key?(:'pattern_with_digits')
@@ -187,6 +195,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if !@integer.nil? && @integer > 100
         invalid_properties.push('invalid value for "integer", must be smaller than or equal to 100.')
@@ -273,6 +282,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if !@integer.nil? && @integer > 100
       return false if !@integer.nil? && @integer < 10
       return false if !@int32.nil? && @int32 > 200
@@ -298,11 +308,15 @@ def valid?
     # Custom attribute writer method with validation
     # @param [Object] integer Value to be assigned
     def integer=(integer)
-      if !integer.nil? && integer > 100
+      if integer.nil?
+        fail ArgumentError, 'integer cannot be nil'
+      end
+
+      if integer > 100
         fail ArgumentError, 'invalid value for "integer", must be smaller than or equal to 100.'
       end
 
-      if !integer.nil? && integer < 10
+      if integer < 10
         fail ArgumentError, 'invalid value for "integer", must be greater than or equal to 10.'
       end
 
@@ -312,11 +326,15 @@ def integer=(integer)
     # Custom attribute writer method with validation
     # @param [Object] int32 Value to be assigned
     def int32=(int32)
-      if !int32.nil? && int32 > 200
+      if int32.nil?
+        fail ArgumentError, 'int32 cannot be nil'
+      end
+
+      if int32 > 200
         fail ArgumentError, 'invalid value for "int32", must be smaller than or equal to 200.'
       end
 
-      if !int32.nil? && int32 < 20
+      if int32 < 20
         fail ArgumentError, 'invalid value for "int32", must be greater than or equal to 20.'
       end
 
@@ -344,11 +362,15 @@ def number=(number)
     # Custom attribute writer method with validation
     # @param [Object] float Value to be assigned
     def float=(float)
-      if !float.nil? && float > 987.6
+      if float.nil?
+        fail ArgumentError, 'float cannot be nil'
+      end
+
+      if float > 987.6
         fail ArgumentError, 'invalid value for "float", must be smaller than or equal to 987.6.'
       end
 
-      if !float.nil? && float < 54.3
+      if float < 54.3
         fail ArgumentError, 'invalid value for "float", must be greater than or equal to 54.3.'
       end
 
@@ -358,11 +380,15 @@ def float=(float)
     # Custom attribute writer method with validation
     # @param [Object] double Value to be assigned
     def double=(double)
-      if !double.nil? && double > 123.4
+      if double.nil?
+        fail ArgumentError, 'double cannot be nil'
+      end
+
+      if double > 123.4
         fail ArgumentError, 'invalid value for "double", must be smaller than or equal to 123.4.'
       end
 
-      if !double.nil? && double < 67.8
+      if double < 67.8
         fail ArgumentError, 'invalid value for "double", must be greater than or equal to 67.8.'
       end
 
@@ -372,8 +398,12 @@ def double=(double)
     # Custom attribute writer method with validation
     # @param [Object] string Value to be assigned
     def string=(string)
+      if string.nil?
+        fail ArgumentError, 'string cannot be nil'
+      end
+
       pattern = Regexp.new(/[a-z]/i)
-      if !string.nil? && string !~ pattern
+      if string !~ pattern
         fail ArgumentError, "invalid value for \"string\", must conform to the pattern #{pattern}."
       end
 
@@ -401,8 +431,12 @@ def password=(password)
     # Custom attribute writer method with validation
     # @param [Object] pattern_with_digits Value to be assigned
     def pattern_with_digits=(pattern_with_digits)
+      if pattern_with_digits.nil?
+        fail ArgumentError, 'pattern_with_digits cannot be nil'
+      end
+
       pattern = Regexp.new(/^\d{10}$/)
-      if !pattern_with_digits.nil? && pattern_with_digits !~ pattern
+      if pattern_with_digits !~ pattern
         fail ArgumentError, "invalid value for \"pattern_with_digits\", must conform to the pattern #{pattern}."
       end
 
@@ -412,8 +446,12 @@ def pattern_with_digits=(pattern_with_digits)
     # Custom attribute writer method with validation
     # @param [Object] pattern_with_digits_and_delimiter Value to be assigned
     def pattern_with_digits_and_delimiter=(pattern_with_digits_and_delimiter)
+      if pattern_with_digits_and_delimiter.nil?
+        fail ArgumentError, 'pattern_with_digits_and_delimiter cannot be nil'
+      end
+
       pattern = Regexp.new(/^image_\d{1,3}$/i)
-      if !pattern_with_digits_and_delimiter.nil? && pattern_with_digits_and_delimiter !~ pattern
+      if pattern_with_digits_and_delimiter !~ pattern
         fail ArgumentError, "invalid value for \"pattern_with_digits_and_delimiter\", must conform to the pattern #{pattern}."
       end
 
@@ -459,37 +497,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb b/samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb
index df54b67cf987..b22799315a3a 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/health_check_result.rb b/samples/client/petstore/ruby/lib/petstore/models/health_check_result.rb
index 12845874f8d7..ef7ee79d79f1 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/health_check_result.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/health_check_result.rb
@@ -67,6 +67,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -74,6 +75,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -101,37 +103,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/list.rb b/samples/client/petstore/ruby/lib/petstore/models/list.rb
index 32065095d9e0..2c0fbf10831d 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/list.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/list.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/map_test.rb b/samples/client/petstore/ruby/lib/petstore/models/map_test.rb
index 181c1c991a14..2f0b4b6aefba 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/map_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/map_test.rb
@@ -119,6 +119,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -126,6 +127,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -156,37 +158,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb b/samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
index 93a1c6c4d747..93cb35097c02 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
@@ -83,6 +83,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -90,6 +91,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -119,37 +121,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/model200_response.rb b/samples/client/petstore/ruby/lib/petstore/models/model200_response.rb
index 9dd11b88dcc8..c857b893607a 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/model200_response.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/model200_response.rb
@@ -74,6 +74,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -81,6 +82,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -109,37 +111,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/model_return.rb b/samples/client/petstore/ruby/lib/petstore/models/model_return.rb
index 1543f71d5ddb..3580c74908d1 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/model_return.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/model_return.rb
@@ -66,6 +66,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -73,6 +74,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -100,37 +102,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/name.rb b/samples/client/petstore/ruby/lib/petstore/models/name.rb
index e0f4d00c0b5b..befba0746d3c 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/name.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/name.rb
@@ -72,6 +72,8 @@ def initialize(attributes = {})
 
       if attributes.key?(:'name')
         self.name = attributes[:'name']
+      else
+        self.name = nil
       end
 
       if attributes.key?(:'snake_case')
@@ -90,6 +92,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -101,6 +104,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       true
     end
@@ -132,37 +136,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/nullable_class.rb b/samples/client/petstore/ruby/lib/petstore/models/nullable_class.rb
index cc768c1a03a6..efbd3bd5fe60 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/nullable_class.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/nullable_class.rb
@@ -175,6 +175,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -182,6 +183,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -220,37 +222,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/number_only.rb b/samples/client/petstore/ruby/lib/petstore/models/number_only.rb
index b04314c703cf..ac3b7457f513 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/number_only.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/number_only.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/object_with_deprecated_fields.rb b/samples/client/petstore/ruby/lib/petstore/models/object_with_deprecated_fields.rb
index 8f511458c6df..9f6558d0a2cf 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/object_with_deprecated_fields.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/object_with_deprecated_fields.rb
@@ -91,6 +91,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -98,6 +99,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -128,37 +130,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/order.rb b/samples/client/petstore/ruby/lib/petstore/models/order.rb
index 9ab55bee6164..e57d1f39f0bf 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/order.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/order.rb
@@ -130,6 +130,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -137,6 +138,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       status_validator = EnumAttributeValidator.new('String', ["placed", "approved", "delivered"])
       return false unless status_validator.valid?(@status)
       true
@@ -181,37 +183,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb b/samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb
index ba83c2a5008f..0e6ec4c25c86 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb
@@ -81,6 +81,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -88,6 +89,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -117,37 +119,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/outer_object_with_enum_property.rb b/samples/client/petstore/ruby/lib/petstore/models/outer_object_with_enum_property.rb
index 4bd272ff2b9e..f2b04477e131 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/outer_object_with_enum_property.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/outer_object_with_enum_property.rb
@@ -81,12 +81,15 @@ def initialize(attributes = {})
 
       if attributes.key?(:'value')
         self.value = attributes[:'value']
+      else
+        self.value = nil
       end
     end
 
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @value.nil?
         invalid_properties.push('invalid value for "value", value cannot be nil.')
@@ -98,6 +101,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @value.nil?
       true
     end
@@ -126,37 +130,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/pet.rb b/samples/client/petstore/ruby/lib/petstore/models/pet.rb
index 78934ccb0301..f71fbd02617f 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/pet.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/pet.rb
@@ -110,12 +110,16 @@ def initialize(attributes = {})
 
       if attributes.key?(:'name')
         self.name = attributes[:'name']
+      else
+        self.name = nil
       end
 
       if attributes.key?(:'photo_urls')
         if (value = attributes[:'photo_urls']).is_a?(Array)
           self.photo_urls = value
         end
+      else
+        self.photo_urls = nil
       end
 
       if attributes.key?(:'tags')
@@ -132,6 +136,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @name.nil?
         invalid_properties.push('invalid value for "name", name cannot be nil.')
@@ -147,6 +152,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @name.nil?
       return false if @photo_urls.nil?
       status_validator = EnumAttributeValidator.new('String', ["available", "pending", "sold"])
@@ -203,37 +209,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb b/samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb
index 8afb713ede88..359bd8fc9b54 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb b/samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb
index d1a049eec39f..250e980e6940 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb
@@ -65,6 +65,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -72,6 +73,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -99,37 +101,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/tag.rb b/samples/client/petstore/ruby/lib/petstore/models/tag.rb
index 894e4c24acc3..e81f82c3927b 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/tag.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/tag.rb
@@ -73,6 +73,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -80,6 +81,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -108,37 +110,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/user.rb b/samples/client/petstore/ruby/lib/petstore/models/user.rb
index e34d1381ea41..a25dd1cd5b3d 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/user.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/user.rb
@@ -122,6 +122,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -129,6 +130,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -163,37 +165,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/spec/custom/base_object_spec.rb b/samples/client/petstore/ruby/spec/custom/base_object_spec.rb
index a603b6d3c442..15e27c6e3b08 100644
--- a/samples/client/petstore/ruby/spec/custom/base_object_spec.rb
+++ b/samples/client/petstore/ruby/spec/custom/base_object_spec.rb
@@ -28,6 +28,68 @@ def self.openapi_types
       :boolean_false_arr => :'Array<Boolean>',
     }
   end
+
+  def initialize(attributes = {})
+    if (!attributes.is_a?(Hash))
+      fail ArgumentError, "The input argument (attributes) must be a hash in `ArrayMapObject` initialize method"
+    end
+
+    # check to see if the attribute exists and convert string to symbol for hash key
+    attributes = attributes.each_with_object({}) { |(k, v), h|
+      if (!self.class.attribute_map.key?(k.to_sym))
+        fail ArgumentError, "`#{k}` is not a valid attribute in `ArrayMapObject`. Please check the name to make sure it's valid. List of attributes: " + self.class.attribute_map.keys.inspect
+      end
+      h[k.to_sym] = v
+    }
+
+    if attributes.key?(:'int_arr')
+      if (value = attributes[:'int_arr']).is_a?(Array)
+        self.int_arr = value
+      end
+    end
+
+    if attributes.key?(:'pet_arr')
+      if (value = attributes[:'pet_arr']).is_a?(Array)
+        self.pet_arr = value
+      end
+    end
+
+    if attributes.key?(:'int_map')
+      if (value = attributes[:'int_map']).is_a?(Hash)
+        self.int_map = value
+      end
+    end
+
+    if attributes.key?(:'pet_map')
+      if (value = attributes[:'pet_map']).is_a?(Hash)
+        self.pet_map = value
+      end
+    end
+
+    if attributes.key?(:'int_arr_map')
+      if (value = attributes[:'int_arr_map']).is_a?(Hash)
+        self.int_arr_map = value
+      end
+    end
+
+    if attributes.key?(:'pet_arr_map')
+      if (value = attributes[:'pet_arr_map']).is_a?(Hash)
+        self.pet_arr_map = value
+      end
+    end
+
+    if attributes.key?(:'boolean_true_arr')
+      if (value = attributes[:'boolean_true_arr']).is_a?(Array)
+        self.boolean_true_arr = value
+      end
+    end
+
+    if attributes.key?(:'boolean_false_arr')
+      if (value = attributes[:'boolean_false_arr']).is_a?(Array)
+        self.boolean_false_arr = value
+      end
+    end
+  end
 end
 
 describe 'BaseObject' do
@@ -41,22 +103,20 @@ def self.openapi_types
   end
 
   describe 'array and map properties' do
-    let(:obj) { ArrayMapObject.new }
-
     let(:data) do
       { int_arr: [123, 456],
-       pet_arr: [{ name: 'Kitty' }],
+       pet_arr: [{ name: 'Kitty', photoUrls: ['www.photo-url.test'] }],
        int_map: { 'int' => 123 },
-       pet_map: { 'pet' => { name: 'Kitty' } },
+       pet_map: { 'pet' => { name: 'Kitty', photoUrls: ['www.photo-url.test'] } },
        int_arr_map: { 'int_arr' => [123, 456] },
-       pet_arr_map: { 'pet_arr' => [{ name: 'Kitty' }] },
+       pet_arr_map: { 'pet_arr' => [{ name: 'Kitty', photoUrls: ['www.photo-url.test'] }] },
        boolean_true_arr:  [true, "true", "TruE", 1, "y", "yes", "1", "t", "T"],
        boolean_false_arr: [false, "", 0, "0", "f", nil, "null", "\ntrue\n"],
       }
     end
 
     it 'works for #build_from_hash' do
-      obj.build_from_hash(data)
+      obj = ArrayMapObject.build_from_hash(data)
 
       expect(obj.int_arr).to match_array([123, 456])
 
@@ -99,7 +159,7 @@ def self.openapi_types
     end
 
     it 'works for #to_hash' do
-      obj.build_from_hash(data)
+      obj = ArrayMapObject.build_from_hash(data)
       expect_data = data.dup
       expect_data[:boolean_true_arr].map! { true }
       expect_data[:boolean_false_arr].map! { false }
diff --git a/samples/client/petstore/ruby/spec/custom/pet_spec.rb b/samples/client/petstore/ruby/spec/custom/pet_spec.rb
index 8b2baf8ba5f2..1fbec557bee4 100644
--- a/samples/client/petstore/ruby/spec/custom/pet_spec.rb
+++ b/samples/client/petstore/ruby/spec/custom/pet_spec.rb
@@ -42,8 +42,7 @@
       expect(pet.category.name).to eq('category unknown')
 
       # test build_from_hash
-      pet2 = Petstore::Pet.new
-      pet2.build_from_hash(pet.to_hash)
+      pet2 = Petstore::Pet.build_from_hash(pet.to_hash)
       expect(pet.to_hash).to eq(pet2.to_hash)
 
       # make sure sub-object has different object id
@@ -157,7 +156,7 @@
     it "should create a pet" do
       id = @pet_id + 1
 
-      pet = Petstore::Pet.new('id' => id, 'name' => "RUBY UNIT TESTING")
+      pet = Petstore::Pet.new('id' => id, 'name' => "RUBY UNIT TESTING", 'photo_urls' => ['www.photo-url.test'])
       result = @pet_api.add_pet(pet)
       # nothing is returned
       expect(result).to be_nil
@@ -165,6 +164,7 @@
       pet = @pet_api.get_pet_by_id(id)
       expect(pet.id).to eq(id)
       expect(pet.name).to eq("RUBY UNIT TESTING")
+      expect(pet.photo_urls).to match_array(['www.photo-url.test'])
 
       @pet_api.delete_pet(id)
     end
@@ -182,8 +182,12 @@
     end
 
     it "should implement eql? and hash" do
-      pet1 = Petstore::Pet.new
-      pet2 = Petstore::Pet.new
+      pet_hash = {
+        name: 'test_name',
+        photo_urls: ['www.photo-url.test']
+      }
+      pet1 = Petstore::Pet.new(pet_hash)
+      pet2 = Petstore::Pet.new(pet_hash)
       expect(pet1).to eq(pet2)
       expect(pet2).to eq(pet1)
       expect(pet1.eql?(pet2)).to eq(true)
diff --git a/samples/client/petstore/ruby/spec/models/format_test_spec.rb b/samples/client/petstore/ruby/spec/models/format_test_spec.rb
index a2cda082f02f..c6408011fbc5 100644
--- a/samples/client/petstore/ruby/spec/models/format_test_spec.rb
+++ b/samples/client/petstore/ruby/spec/models/format_test_spec.rb
@@ -20,7 +20,12 @@
 describe 'FormatTest' do
   before do
     # run before each test
-    @instance = Petstore::FormatTest.new
+    @instance = Petstore::FormatTest.new({
+      number: 65,
+      byte: '1234356',
+      date: Date.parse('2007-12-03T10:15:30+01:00'),
+      password: 'password123'
+    })
   end
 
   after do
diff --git a/samples/client/petstore/ruby/spec/models/pet_spec.rb b/samples/client/petstore/ruby/spec/models/pet_spec.rb
index f8a46865240f..08a4e8f61c98 100644
--- a/samples/client/petstore/ruby/spec/models/pet_spec.rb
+++ b/samples/client/petstore/ruby/spec/models/pet_spec.rb
@@ -20,7 +20,7 @@
 describe 'Pet' do
   before do
     # run before each test
-    @instance = Petstore::Pet.new
+    @instance = Petstore::Pet.new({ name: 'Kitty', photo_urls: ['www.photo-url.test'] })
   end
 
   after do
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/array_alias.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/array_alias.rb
index b69287ef2496..da0c5b194853 100644
--- a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/array_alias.rb
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/array_alias.rb
@@ -60,6 +60,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = super
       invalid_properties
     end
@@ -67,6 +68,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true && super
     end
 
@@ -93,38 +95,31 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/map_alias.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/map_alias.rb
index f368c8bbde55..7d927d832331 100644
--- a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/map_alias.rb
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/map_alias.rb
@@ -57,6 +57,7 @@ def initialize(attributes = {})
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       invalid_properties
     end
@@ -64,6 +65,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       true
     end
 
@@ -90,37 +92,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)