import java.net.*;
import java.io.*;

public class MulticastSniffer {

  public static void main(String[] args) {
  
    InetAddress group = null;
    int port = 0;
  
    // read the address from the command line
    try {
      group = InetAddress.getByName(args[0]);
      port = Integer.parseInt(args[1]);
    }  // end try
    catch (Exception ex) {
      // ArrayIndexOutOfBoundsException, NumberFormatException,
      // or UnknownHostException
      System.err.println(
       "Usage: java MulticastSniffer multicast_address port");
      System.exit(1);
    }
  
    MulticastSocket ms = null;
  
    try {
      ms = new MulticastSocket(port);
      ms.joinGroup(group);
      
      byte[] buffer = new byte[8192];
      while (true) {
        DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
        ms.receive(dp);
        String s = new String(dp.getData());
        System.out.println(s);
      }
    }
    catch (IOException ex) {
      System.err.println(ex);
    }
    finally {
      if (ms != null) {
        try {
          ms.leaveGroup(group);
          ms.close();
        }
        catch (IOException ex) {} 
      }
    } 
  
  }

}