package test;

import java.io.IOException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

public class Server {  

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

    	DatagramSocket ds=new DatagramSocket(3000);

    	String str="Hello";

    	DatagramPacket dp=new DatagramPacket(str.getBytes(),str.length(),InetAddress.getByName("localhost"),9000);

    	ds.send(dp);

    	ds.close();

    }

}

package test;

import java.io.IOException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

public class Client{

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

		DatagramSocket ds=new DatagramSocket(9000);

		byte b[]=new byte[1024];

		DatagramPacket dp=new DatagramPacket(b,1024);

		ds.receive(dp);

		String str=new String(dp.getData(),0,dp.getLength())+"from"+dp.getAddress().getHostAddress()+":"+dp.getPort();

		System.out.println(str);

		ds.close();

	}

};