import java.net.*; import java.io.*; public class UDPEchoClient { public final static int DEFAULT_PORT = 7; public static void main(String[] args) { String hostname = "localhost"; int port = DEFAULT_PORT; if (args.length > 0) { hostname = args[0]; } try { InetAddress ia = InetAddress.getByName(hostname); Thread sender = new SenderThread(ia, DEFAULT_PORT); sender.start(); Thread receiver = new ReceiverThread(sender.getSocket()); receiver.start(); } catch (UnknownHostException ex) { System.err.println(ex); } catch (SocketException ex) { System.err.println(ex); } } // end main }