String url = "http:
String url = "http: hostName + ":" + port + ENDPOINT_PATH_ON_SERVER;
    public String getCallbackURL() {        assert serverSocket != null;        String hostName = null;        try {            hostName = InetAddress.getLocalHost().getHostAddress();        } catch (UnknownHostException e) {            throw new RuntimeException(e);        }        // serverSocket.getInetAddress().getHostName();        assert hostName != null;        String url = "http://" + hostName + ":" + port + ENDPOINT_PATH_ON_SERVER;        return url;    }