@GET
public String getList() {
    return response[0];
}

@ApplicationPath("webresources")
public class MyApplication extends Application {

    public MyApplication();
}

/WEB-INF/
/WEB-INF/classes/
/WEB-INF/classes/org/
/WEB-INF/classes/org/javaee7/jaxrs/
/WEB-INF/classes/org/javaee7/jaxrs/asyncclient/
/WEB-INF/classes/org/javaee7/jaxrs/asyncclient/MyResource.class
/WEB-INF/classes/org/javaee7/jaxrs/asyncclient/MyApplication.class

@Deployment(testable = false)
public static WebArchive createDeployment() {
   return ShrinkWrap.create(WebArchive.class)
         .addClasses(MyApplication.class, MyResource.class);
}

@Before
public void setUpClass() throws MalformedURLException {
    Client client = ClientBuilder.newClient();
    target = client.target(URI.create(new URL(base, "webresources/fruits").toExternalForm()));
}

@Test
public void testPollingResponse() throws InterruptedException, ExecutionException {
    Future<Response> r1 = target.request().async().get(); (1)
    String response = r1.get().readEntity(String.class);  (2)
    assertEquals("apple", response);                      (3)
}

@Test
public void testPollingString() throws InterruptedException, ExecutionException {
    Future<String> r1 = target.request().async().get(String.class); (1)
    String response = r1.get();                                     (2)
    assertEquals("apple", response);                                (3)
}

@Test
public void testInvocationCallback() throws InterruptedException, ExecutionException {
        target.request().async().get(new InvocationCallback<String>() { (1)

            @Override
            public void completed(String r) {                           (2)
                assertEquals("apple", r);
            }

            @Override
            public void failed(Throwable t) {                           (3)
                fail(t.getMessage());
            }

        });
}