Get "caption": "Authentication problem" when HttpPost to vaadin

I am trying to httpPost vaadin project url

    String url = "http://localhost:8080/ProjectName/";
    client = new DefaultHttpClient();
    HttpPost request = new HttpPost(url + parameter); // here you put the entire URL with the GET parameters
    HttpResponse response = client.execute(request);
    // from here is postprocessing to handle the response, in my case JSON

    BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
    String line = "";
    StringBuilder sb = new StringBuilder("");

    while ((line = rd.readLine()) != null) {
        sb.append(line);
    }

Returning string is like below.

Why always returning
: “caption”: “Authentication problem”, and : “caption”: “Communication problem” . ???
What do i have to do to overcome these problems?

ProjectName html, body {height:100%;margin:0;}
You have to enable javascript in your browser to use an application built with Vaadin.

Hi,

you can’t really use a Vaadin application without a browser (with JavaScript support). You should maybe consider setting up a REST service instead?

-Olli