oneOf not able to generate java class

Description

openapi-generator for java is not able to generate class for oneOf field

/Users/....../CustomClass.java:[23,41] cannot find symbol
[ERROR] symbol: class OneOfstringinteger

CustomClass.java class is created with the field

public static final String SERIALIZED_NAME_FIELD_VALUE = "fieldValue";
@SerializedName(SERIALIZED_NAME_FIELD_VALUE)
private OneOfstringinteger fieldValue = null;

But OneOfstringinteger is not getting created.

Swagger-codegen version

org.openapitools openapi-generator-maven-plugin 4.1.1

Swagger declaration file content or url

fieldValue:
    oneOf:
      - type: string
      - type: integer

Command line used for generation

mvn clean install takes care of it

Steps to reproduce

trying to build the project by maven command

Related issues/PRs

Suggest a fix/enhancement

open-api generator for java is not able to generate a class for oneOf type for primitive objects (string, integer, number etc).

tried with objects also but same error came:

fieldValue:
    oneOf:
      - $ref: '#/definitions/StringValue'
      - $ref: '#/definitions/NumberValue'

definitions:
  StringValue:
    type: object
    properties:
      name:
        type: string

  NumberValue:
    type: object
    properties:
      name:
        type: number

cannot find symbol
[ERROR]   symbol:   class OneOfStringValueNumberValue

Start with the OpenAPI schema's oneOf definitions and the generated CustomClass.java, then run the reported mvn clean install command to reproduce the missing OneOfstringinteger or OneOfStringValueNumberValue class. Done means the required Java classes are generated for primitive and referenced oneOf members and the Maven build no longer reports cannot find symbol.