reCaptcha response is blank

Question

I have implemented reCaptcha in the application I am working on. Somehow I am getting a blank reCaptcha response.

It works fine with localhost, but I am having a problem in upper environments like DEV, TEST. User response is being verified on server side (servlet).

Anyone having idea or faced similar problem ? Let me know if you need more info.

    String userresponse = (String) request.getAttribute("g-recaptcha-response");

    URL url = null;
    HttpURLConnection conn = null;
    String line, outputString = "";
    try {
        url = new URL(https://www.google.com/recaptcha/api/siteverify?secret=privateKey&response=userresponse);

        conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        BufferedReader reader = new BufferedReader(
                new InputStreamReader(conn.getInputStream()));
        while ((line = reader.readLine()) != null) {
            outputString += line;
        }
        Log.debug("Google response is :- "+outputString);
    } catch (IOException e) {
        e.printStackTrace();
    }