diff --git a/sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala b/sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala
index 1a1954281cd06..9954ae4c44512 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala
@@ -73,8 +73,10 @@ class DataFrameReader private[sql](sparkSession: SparkSession) extends Logging {
    * @since 1.4.0
    */
   def schema(schema: StructType): DataFrameReader = {
-    val replaced = CharVarcharUtils.failIfHasCharVarchar(schema).asInstanceOf[StructType]
-    this.userSpecifiedSchema = Option(replaced)
+    if (schema != null) {
+      val replaced = CharVarcharUtils.failIfHasCharVarchar(schema).asInstanceOf[StructType]
+      this.userSpecifiedSchema = Option(replaced)
+    }
     this
   }
 
@@ -90,10 +92,7 @@ class DataFrameReader private[sql](sparkSession: SparkSession) extends Logging {
    * @since 2.3.0
    */
   def schema(schemaString: String): DataFrameReader = {
-    val rawSchema = StructType.fromDDL(schemaString)
-    val schema = CharVarcharUtils.failIfHasCharVarchar(rawSchema).asInstanceOf[StructType]
-    this.userSpecifiedSchema = Option(schema)
-    this
+    schema(StructType.fromDDL(schemaString))
   }
 
   /**
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/streaming/DataStreamReader.scala b/sql/core/src/main/scala/org/apache/spark/sql/streaming/DataStreamReader.scala
index 2ed2487c83b01..a6913fab97a40 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/streaming/DataStreamReader.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/streaming/DataStreamReader.scala
@@ -64,8 +64,10 @@ final class DataStreamReader private[sql](sparkSession: SparkSession) extends Lo
    * @since 2.0.0
    */
   def schema(schema: StructType): DataStreamReader = {
-    val replaced = CharVarcharUtils.failIfHasCharVarchar(schema).asInstanceOf[StructType]
-    this.userSpecifiedSchema = Option(replaced)
+    if (schema != null) {
+      val replaced = CharVarcharUtils.failIfHasCharVarchar(schema).asInstanceOf[StructType]
+      this.userSpecifiedSchema = Option(replaced)
+    }
     this
   }
 
@@ -77,10 +79,7 @@ final class DataStreamReader private[sql](sparkSession: SparkSession) extends Lo
    * @since 2.3.0
    */
   def schema(schemaString: String): DataStreamReader = {
-    val rawSchema = StructType.fromDDL(schemaString)
-    val schema = CharVarcharUtils.failIfHasCharVarchar(rawSchema).asInstanceOf[StructType]
-    this.userSpecifiedSchema = Option(schema)
-    this
+    schema(StructType.fromDDL(schemaString))
   }
 
   /**