[JAVA] generating Map with jaxrs-reasteasy does not import the hashmap

[tnmtechnologies]

Description

The description is the same as the one described here swagger-codegen/issues/8876 but for the jaxrs-resteasy generator.

openapi-generator version

3.3.1

OpenAPI declaration file content or url

The issue occurs with this piece of yaml definition:

      responses:
        '200':
          description: Expected response to a valid request
          content:
            application/3gppHal+json:
              schema:
                type: object
                properties:
                  _links:
                    type: object
                    description: 'List of the URI of NF instances. It has two members whose names are item and self. The item one contains an array of URIs.'
                    additionalProperties:
                      $ref: './TS29571_CommonData.yaml#/components/schemas/LinksValueSchema'

Command line used for generation

Steps to reproduce

Related issues/PRs

swagger-codegen/issues/8876

Suggest a fix/enhancement