Jersey RESTful Webサービスにエンティティデータが埋め込まれたファイルをアップロードするにはどうすればよいですか?

@POST
@Path("/upload2")
@Consumes({MediaType.MULTIPART_FORM_DATA, MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
public Response uploadFileWithData(
    @FormDataParam("file") InputStream fileInputStream,
    @FormDataParam("file") FormDataContentDisposition contentDispositionHeader,
    @FormDataParam("emp") Employee emp) {

    // Business logic

}

@Test
public void testGetIt() throws Exception {
    
    final Client client = ClientBuilder.newBuilder()
        .register(MultiPartFeature.class)
        .build();
    WebTarget t = client.target(Main.BASE_URI).path("multipart").path("upload2");

    FileDataBodyPart filePart = new FileDataBodyPart("file", 
                                             new File("stackoverflow.png"));
    String empPartJson
            = "{ ... employee data as JSON ... }";

    MultiPart multipartEntity = new FormDataMultiPart()
            .field("emp", empPartJson, MediaType.APPLICATION_JSON_TYPE)
            .bodyPart(filePart);
          
    Response response = t.request().post(
            Entity.entity(multipartEntity, multipartEntity.getMediaType()));
    System.out.println(response.getStatus());
    System.out.println(response.readEntity(String.class));

    response.close();
}