import java.net.*; 
import java.io.*; 
public class MulticastPeer{ 
  public static void main(String args[]){ 
    // args give message contents & destination multicast group(e.g."228.5.6.7")
    MulticastSocket s =null; 
    try { 
      InetAddress group = InetAddress.getByName(args[1]); 
      s = new MulticastSocket(6789); 
      s.joinGroup(group); 
      byte [] m = args[0].getBytes(); 
      DatagramPacket messageOut = new DatagramPacket(m, m.length, group, 6789);
      s.send(messageOut); 
      // get messages from others in group 
      byte[] buffer = new byte[1000]; 
      for(int i=0; i< 3; i++) { 
        DatagramPacket messageIn = new DatagramPacket(buffer, buffer.length); 
        s.receive(messageIn); 
        System.out.println("Received:" + new String(messageIn.getData())); 
      } 
      s.leaveGroup(group); 
    }
    catch (SocketException e){System.out.println("Socket: " + e.getMessage());}
    catch (IOException e){System.out.println("IO: " + e.getMessage());}  
    finally { if(s != null) s.close();} 
  } 
}