Simple Chat program using UDP

import java.net.*;

import java.io.*;

public class simpleChat {

public static void main(String args[]) throws Exception {

DatagramSocket ioSocket;

String toName, userIn;

byte sendBuffer[] = new byte[128];

byte receiveBuffer[] = new byte[128];

DatagramPacket sendPacket = new DatagramPacket(sendBuffer, 128);

DatagramPacket receivePacket = new DatagramPacket(receiveBuffer, 128);

BufferedReader in = new BufferedReader(

new InputStreamReader( System.in));

int ioPort = 111;

receiverPort = ioPort;

if (args.length > 0)

toName = args[0];

else

toName = "localhost";

if (toName.equals("localhost"))

receiverPort = 222;

try { ioSocket = new DatagramSocket(ioPort); }

catch (Exception e) {

ioPort = 222; receiverPort = 111;

ioSocket = new DatagramSocket(ioPort);

}

System.out.println("simpleChat on port " + ioPort + ". Ctrl Z to quit.");

while ((userIn=in.readLine())!=null) {

sendBuffer= userIn.getBytes();

sendPacket = new DatagramPacket( sendBuffer, sendBuffer.length,

InetAddress.getByName(toName), receiverPort);

ioSocket.send(sendPacket);

ioSocket.receive(receivePacket);

System.out.println( "Received " + new String(receivePacket.getData(),

0, receivePacket.getLength()));

}

}

}

/* Output:

Client1:

C:\Program Files\Java\CM13>java simpleChat

simpleChat on port 222. Ctrl Z to quit.

Hi

Received So u r in the league

Yes i m also a java programmer

Clinet2:

C:\Program Files\Java\CM13>java simpleChat

simpleChat on port 111. Ctrl Z to quit.

Hello

Received Hi

So u r in the league

Received Yes i m also a java programmer