package bingo.shared;import java.net.*;import java.io.*;public abstract class ListenerThread extends Thread {    boolean stopListening = false;    MulticastSocket socket;    private InetAddress group;    private String groupString;    public ListenerThread(String groupString)        throws UnknownHostException, IOException    {	super();	this.groupString = groupString;        this.group = InetAddress.getByName(groupString);        socket = new MulticastSocket(Constants.portNumber);	socket.joinGroup(group);    }    public void stopListening() throws IOException{	stopListening = true;	socket.leaveGroup(group);	socket.close();    }}