import java.net.*;

public class Cl {
	public static void main(String args[]) {
		DatagramSocket dsock;
		DatagramPacket dpack;
		int p;
		byte b[]=new byte[20];
		try {
			dsock=new DatagramSocket(5200);
			dpack=new DatagramPacket("test".getBytes(),"test".length(),InetAddress.getByName("localhost"),4200);			
			dsock.send(dpack);
			dpack=new DatagramPacket(new byte[20],20);
			dsock.receive(dpack);
			System.out.println("received packet from "+dpack.getAddress().getHostName());
			System.out.println(new String(dpack.getData()));
		} catch (Exception ex) {System.out.println(ex.getMessage());}
	}
}