Mockserver does not catch my requests

I am trying to use http://ift.tt/1iJmeii to mock a REST service. My source code is trying to make a GET on: http://ift.tt/1Hi2RaD

I would like to mock this service. I have currently written in my code:

mockServer = startClientAndServer(1080);
proxy = startClientAndProxy(1090);

new MockServerClient("127.0.0.1", 1080)
        .when(
                request()
                        .withMethod("GET")
                        .withPath("/computeMetadata/v1/project/project-id"),
                exactly(1)
        )
        .respond(
                response()
                        .withStatusCode(200)
                        .withBody("the_project_id")
        );

When I run the mock server client and I then the source code which makes the request, I am still getting a socket exception instead of the reply of the mock server. How can I fix my code to mock http://ift.tt/1Hi2RaD? I have fully read the mock-server documentation but I do not understand it very well.