DataType nested class #626

Description

The Java contract API appears to use inconsistent names for nested @DataType classes when creating schema references and registering types.

TypeRegistryImpl.addDataType(Class<?>) registers a data type using DataTypeDefinitionImpl.getSimpleName(). For a nested class such as Outer.Inner, Class.getSimpleName() returns Inner, so the registry key is Inner.

However, TypeSchema.typeConvert(Class<?>) uses Class.getTypeName() and passes that name to updateSchemaForClass(...). For Outer.Inner, the class name contains Outer$Inner. In TypeSchema.updateSchemaForClass(...), this line:

schema.put("$ref", "#/components/schemas/" + className.substring(className.lastIndexOf('.') + 1));

produces:

#/components/schemas/Outer$Inner

instead of:

#/components/schemas/Inner

This creates a registry lookup mismatch. During deserialization, the schema reference resolves to Outer$Inner, but the type registry contains the data type under Inner. The lookup returns null, and JSONTransactionSerializer.createComponentInstance(...) then throws a NullPointerException when it tries to use the missing definition.

The reference mismatch can also be observed directly by calling TypeSchema.typeConvert(Outer.Inner.class) from a smart contract: its "$ref" is #/components/schemas/Outer$Inner, while the registry uses the key Inner.

Steps to reproduce

1. Define a nested @DataType class:

   public class Outer {
       @DataType
       public static class Inner {
           @Property
           private String value;
   
           public Inner() {
           }
       }
   }

2. Define a contract transaction that accepts the nested data type:

   @Contract(name = "NestedTypeContract")
   public class NestedTypeContract implements ContractInterface {
       @Transaction
       public Outer.Inner echo(final Context context, final Outer.Inner input) {
           return input;
       }
   
       @Transaction
       public String inspectSchema(final Context context) {
           return TypeSchema.typeConvert(Outer.Inner.class).getRef();
       }
   }

3. Start the contract so the shim scans the @DataType class. The type registry registers Outer.Inner under its simple name:

   Inner
   

4. Invoke inspectSchema. Observe that TypeSchema.typeConvert(Outer.Inner.class).getRef() returns:

   #/components/schemas/Outer$Inner
   

   This differs from the registry key, Inner.

5. Submit the echo transaction with a JSON argument representing Outer.Inner:

   {"value":"test"}

6. Observe that deserialization attempts to look up Outer$Inner in the type registry, gets null, and fails with a NullPointerException in JSONTransactionSerializer.createComponentInstance().