openapi yaml file having callback not generating the callback code

I am trying to generate API & Model classes (java files) from OpenAPI (3.0.x) yaml file through swagger code generator (Server side). I am using suggestions from the swagger official website below:

https://swagger.io/docs/specification/callbacks/

First time I generated spring java classes (API & Models) without callback and then I generated the java classes with callback. But both are giving me same API and Model java files. Nowhere I am seeing any extra lines of code generated for adding callback in the yaml file. I am using https://editor.swagger.io/ (Swagger Smartbear) to generate the spring server side code. Please help.

Without callback :

openapi: 3.0.0
info:
  version: 0.0.0
  title: test
paths:
  /subscribe:
    post:
      summary: Subscribe to a webhook
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                callbackUrl:   # Callback URL
                  type: string
                  format: uri
                  example: https://myserver.com/send/callback/here
              required:
                - callbackUrl
      responses:
        '201':
          description: Webhook created

With Callback :

openapi: 3.0.0
info:
  version: 0.0.0
  title: test
paths:
  /subscribe:
    post:
      summary: Subscribe to a webhook
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                callbackUrl:   # Callback URL
                  type: string
                  format: uri
                  example: https://myserver.com/send/callback/here
              required:
                - callbackUrl
      responses:
        '201':
          description: Webhook created
      callbacks:   # Callback definition
        myEvent:   # Event name
          '{$request.body#/callbackUrl}':   # The callback URL,
                                            # Refers to the passed URL
            post:
              requestBody:   # Contents of the callback message
                required: true
                content:
                  application/json:
                    schema:
                      type: object
                      properties:
                        message:
                          type: string
                          example: Some event happened
                      required:
                        - message
              responses:   # Expected responses to the callback message
                '200':
                  description: Your server returns this code if it accepts the callback

Reproduce the issue in editor.swagger.io using the supplied OpenAPI 3.0 YAML examples and compare the generated Spring server API and model classes. Start by tracing callback handling in swagger-codegen's OpenAPI parser and template-driven generation flow; done means callback behavior is correctly reflected in generated output or its unsupported status is clearly established with regression coverage.