public void stopServer()
	{
		try
		{
			UDPsocket.close();
			userMap.clear();
			listener.interrupt();
			ping.interrupt();

			GUI.addMessage("Server stopped");
			GUI.btnStartServer.setVisible(true);
			GUI.btnStopServer.setVisible(false);
		} catch (Exception e)
		{
			GUI.addMessage("Unable to stop server: " + e.getMessage());
			e.printStackTrace();
		}
	}