[java-client][jersey2] ignore getter when serializing

Given this spec:

openapi: 3.0.1
info:
  title: ping test
  version: '1.0'
servers:
  - url: 'http://localhost:9999/'
paths:
  /ping:
    post:
      operationId: postPing
      requestBody:
        content:
          'application/json':
             schema:
               $ref: "#/components/schemas/SomeObj"
      responses:
        '201':
          description: OK
          content:
            'application/json':
               schema:
                 $ref: "#/components/schemas/SomeObj"
components:
  schemas:
    SomeObj:
      type: object
      properties:
        $_type:
          type: string
        id:
          type: integer
          format: int64
        name:
          type: string

It generates:

public class SomeObj {
  @JsonProperty("$_type")
  private String $type;

  //...

  public SomeObj $type(String $type) {
    this.$type = $type;
    return this;
  }

   /**
   * Get $type
   * @return $type
  **/
  @javax.annotation.Nullable
  @ApiModelProperty(value = "")
  public String get$Type() {
    return $type;
  }

  public void set$Type(String $type) {
    this.$type = $type;
  }

  //...
}

Because the getter get$Type() looks a little bit different than the $type field annotated with @JsonProperty("$_type"), jackson serializes the object like this:

{ "$_type": "someValue", "$Type": "someValue", "id": 42, "name": "test"}

Because all fields are generated with a proper @JsonProperty, discovery of the getters should be disabled when doing the serialization.

This can be configured in the generated JSON class:
https://github.com/OpenAPITools/openapi-generator/blob/411199bc9954c14779201e569d5f475ffb3e4be0/samples/client/petstore/java/jersey2/src/main/java/org/openapitools/client/JSON.java#L16-L30

By adding a disable command for:

• MapperFeature.AUTO_DETECT_CREATORS
• MapperFeature.AUTO_DETECT_FIELDS
• MapperFeature.AUTO_DETECT_GETTERS
• MapperFeature.AUTO_DETECT_IS_GETTERS

More info: https://stackoverflow.com/questions/25893985/jackson-how-to-serialize-only-annotated-properties

Start with the generated samples/client/petstore/java/jersey2/src/main/java/org/openapitools/client/JSON.java file and trace how its Jackson mapper configuration is produced. Check the requested MapperFeature settings and verify that a generated object serializes only the annotated properties, without the duplicate getter-derived property.