Add null type only test to Java okhttp-gson client

[wing328]

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---

Summary by cubic

Adds a null-only schema property to the Java okhttp-gson 3.1 petstore sample to validate OpenAPI 3.1 type: null handling. This ensures the generator emits a nullable Object field and includes it in equality, hashing, and field validation.

• Spec: adds second_property with type: null and description "just null type".
• Model PetWithTypesObjectNullAndRef: new secondProperty (Object, @javax.annotation.Nullable), included in equals, hashCode, toString, and openapiFields.
• Docs: PetWithTypesObjectNullAndRef now lists secondProperty as optional Object with the description.
• Adds JsonNullable helpers; they are not used and do not change behavior.

Review Notes

• Focus on generated Java for okhttp-gson to confirm type: null maps to a nullable Object and passes validation.
• Regenerate samples to verify outputs stay consistent across generators.

^{Written for commit 9bda43e. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 4 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/model/PetWithTypesObjectNullAndRef.java">

<violation number="1" location="samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/model/PetWithTypesObjectNullAndRef.java:166">
P3: The `equalsNullable` and `hashCodeNullable` helper methods are never called, and the `JsonNullable` import exists only to support them. `equals`/`hashCode` use plain `Objects.equals`/`Objects.hash` on the `Object` field, so both helpers are dead code. Remove both methods and the `JsonNullable` import.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

P3: The equalsNullable and hashCodeNullable helper methods are never called, and the JsonNullable import exists only to support them. equals/hashCode use plain Objects.equals/Objects.hash on the Object field, so both helpers are dead code. Remove both methods and the JsonNullable import.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/model/PetWithTypesObjectNullAndRef.java, line 166:

<comment>The `equalsNullable` and `hashCodeNullable` helper methods are never called, and the `JsonNullable` import exists only to support them. `equals`/`hashCode` use plain `Objects.equals`/`Objects.hash` on the `Object` field, so both helpers are dead code. Remove both methods and the `JsonNullable` import.</comment>

<file context>
@@ -133,20 +158,33 @@ public boolean equals(Object o) {
         Objects.equals(this.additionalProperties, petWithTypesObjectNullAndRef.additionalProperties);
   }
 
+  private static <T> boolean equalsNullable(JsonNullable<T> a, JsonNullable<T> b) {
+    return a == b || (a != null && b != null && a.isPresent() && b.isPresent() && Objects.deepEquals(a.get(), b.get()));
+  }
</file context>