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

class MCServer
{
　 public static void main (String[] args) throws IOException
　 {
　　 System.out.println ("Server starting...\n");

　　// Create a MulticastSocket not bound to any port.

　　MulticastSocket s = new MulticastSocket ();

　　// Because MulticastSocket subclasses DatagramSocket, it is
　　 // legal to replace MulticastSocket s = new MulticastSocket ();
　　 // with the following line.

　　 // DatagramSocket s = new DatagramSocket ();

　　// Obtain an InetAddress object that contains the multicast
　　 // group address 231.0.0.1. The InetAddress object is used by
　　 // DatagramPacket.

　　InetAddress group = InetAddress.getByName ("231.0.0.1");

　　// Create a DatagramPacket object that encapsulates a reference
　　 // to a byte array (later) and destination address
　　 // information. The destination address consists of the
　　 // multicast group address (as stored in the InetAddress object)
　　 // and port number 10000 -- the port to which multicast datagram
　　 // packets are sent. (Note: The dummy array is used to prevent a
　　 // NullPointerException object being thrown from the
　　 // DatagramPacket constructor.)

　　byte [] dummy = new byte [0];

　　DatagramPacket dgp = new DatagramPacket (dummy,
　　　　 0,
　　　　 group,
　　　　 10000);

　　// Send 30000 Strings to the port.

　　for (int i = 0; i < 30000; i++)
　　 {
　　　 // Create an array of bytes from a String. The platform's
　　　 // default character set is used to convert from Unicode
　　　 // characters to bytes.

　　　byte [] buffer = ("Video line " + i).getBytes ();

　　　// Establish the byte array as the datagram packet's
　　　 // buffer.

　　　dgp.setData (buffer);

　　　// Establish the byte array's length as the length of the
　　　 // datagram packet's buffer.

　　　dgp.setLength (buffer.length);

　　　// Send the datagram to all members of the multicast group
　　　 // that listen on port 10000.

　　　s.send (dgp);
　　 }

　　// Close the socket.

　　s.close ();
　 }
}