Program freeze when calling Server method in Java

Question

I have a basic GUI in Java where there is a JButton ,I have given a functionality to start the Server with that button. But when I click the button the program freezes. Is it because of the while loop ? If so how can I overcome this?

Server Code

 void connect_clients()
{
    try {
        ServerSocket listener = new ServerSocket(7700);
        try {
            while (true) {
                Socket socket = listener.accept();
                try {
                    PrintWriter out =
                            new PrintWriter(socket.getOutputStream(), true);
                    out.println(new Date().toString());
                }

                finally {
                    socket.close();
                }
            }
        }
        finally {
            listener.close();
        }
    }
    catch (IOException ex) {
        Logger.getLogger(Test_Frame.class.getName()).log(Level.SEVERE, null, ex);
    }   
}

Answer 1

Here is method explanation of ServerSocket.accept() :

Listens for a connection to be made to this socket and accepts it. The method blocks until a connection is made.

Until there is data input to socket, your program will freeze. If it's another problem, please check your logs. There may be another problem.

Answer 2

Your program is freezing because you are blocking the UI thread. You need to post this on a separate thread:

public void postListen()
{
    new Thread(new Runnable()
    {
        public void run()
        {
            connect_clients();
        }

    }).start();
}

Call that method instead and it should run the connect_clients() method on a separate thread. The new thread will block until a client connects.