Java MulticastSocket .setInterface (InetAddress inf)

public void setInterface(InetAddress inf)   throws SocketException

import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.MulticastSocket;
import java.net.NetworkInterface;
//  ww  w  .  ja  v  a 2 s  . c  om
public class Main {
  public static void main(String[] args) throws Exception {
    int port = 0;
    byte ttl = (byte) 1;

    byte[] data = "Here's some multicast data\r\n".getBytes();
    DatagramPacket dp = new DatagramPacket(data, data.length, InetAddress.getByName("google.com"), port);

    MulticastSocket ms = new MulticastSocket(InetSocketAddress.createUnresolved("google.com", 8080));
    ms.joinGroup(InetSocketAddress.createUnresolved("127.0.0.1",8080),NetworkInterface.getByIndex(0));
    for (int i = 1; i < 10; i++) {
      ms.send(dp, ttl);
    }
    ms.setInterface(InetAddress.getByName("google.com"));

    
    ms.close();
  }

}