JAX-RS Swagger codegen does not handle enum defined in external json file

If an enum is added into external json file Swagger Codegen does not generate model correctly.
Example project: https://github.com/abhijith-prabhakar/swagger-ref-error-demo/blob/master/src/main/resources/v1/schema/title/title.json#L43

 "media_types": {
      "description": "different media types",
      "type": "array",
      "items" : {
        "type" : "string",
        "enum" : [ "application/pdf", "application/json" ]
      }
    },

Generated Code

/**
   * different media types
   */
  public enum List<MediaTypesEnum> {
    PDF("application/pdf"),

        JSON("application/json");
    private List<String> value;

    List<MediaTypesEnum>(List<String> value) {
      this.value = value;
    }

    @Override
    @JsonValue
    public String toString() {
      return String.valueOf(value);
    }
  }

Start with the external schema at src/main/resources/v1/schema/title/title.json#L43 in the linked example project and inspect the generated JAX-RS enum shown in the issue. Trace how Swagger Codegen handles the external JSON definition and compare the generated model with the schema. Done means an external enum inside an array generates a valid Java model with the expected enum values.