Java APIs

hi all, i need your help concerning the ip 230.0.0.1, when i wanna joinGroup it with my client, an exception occured, so what is the problem?

ex:
MulticastSocket msocket = new MulticastSocket (5555);
InetAddress group = InetAddress.getByName ("230.0.0.1");
msocket.joinGroup (group); // here is an runtime exception thrown

show the code down:

************************* the code ***********************************


//In the name of ALLAH most gracious most merciful:

this exception on both win & linux
----------------------------------------------------------------------------------------------------
// Constants : contain the server's port no.

package messenger;

public interface Constants {
static final int SRV_PORT = 6666;
}

----------------------------------------------------------------------------------------------------
// The server in Server.java

package messenger;

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

public class Server implements Constants{

private static DatagramSocket dsocket;
private static DatagramPacket dpacket;

public static void displayStarting() throws InterruptedException{
System.out.print("Starting server .");
for ( int i = 0; i < 5; i++){
System.out.print(".");
Thread.sleep(200);
}
}

public static void main(String[] args) {
boolean opening = true;
try{
displayStarting();
// listening on the server dedecated port :
dsocket = new DatagramSocket(SRV_PORT);

while ( opening ){
dpacket = new DatagramPacket(new byte[5000], 5000);
// waiting a packet to come:
dsocket.receive(dpacket);

// extracting client info:
int clientPort = dpacket.getPort();
//InetAddress address = dpacket.getAddress(); //I will never need cause i send info to a shared IP add

// preparing the packet to send:
InetAddress sharedAdd = InetAddress.getByName("230.0.0.1");
dpacket = new DatagramPacket(dpacket.getData(), dpacket.getData().length, sharedAdd, clientPort);

dsocket.send(dpacket);
}
}catch(SocketException e){
e.printStackTrace();
}catch (IOException e){
e.printStackTrace();
}catch (InterruptedException e){
e.printStackTrace();
}finally{
dsocket.close();
}
}

}
----------------------------------------------------------------------------------------------------
// the client, the class that contains the problem

import java.net.*;
import java.io.*;
import messenger.Constants; // to obtain the server port no. : SRV_PORT


public class Client implements Constants{

private static MulticastSocket msocket ;
private static InetAddress group;
private static DatagramPacket dpacket ;

private static BufferedReader stdIn = new BufferedReader( new InputStreamReader( System.in));

public static void main(String[] args) {
if ( args.length != 1){
System.out.println("Usage : java -jar Messenger-Client <hostname>"+
"\nwhere <hostname> is the name of the machine that hosted the server program");
return;
}

try{
int client_port = 5555;

msocket = new MulticastSocket(client_port);
group = InetAddress.getByName("230.0.0.1");
msocket.joinGroup(group); // ===>> here is the problem, an exception thrown, the details is at the bottom.

String line ;
while ( ( line = stdIn.readLine()) != null ){
// preparing packet to send:
InetAddress hostAdd = InetAddress.getByName(args[0]);
dpacket = new DatagramPacket(line.getBytes(), line.getBytes().length, hostAdd, SRV_PORT);
msocket.send(dpacket);

// waiting server respone:
msocket.receive(dpacket);
System.out.println(new String(dpacket.getData()));
}

}catch (NumberFormatException e){
e.printStackTrace();
}catch (IOException e){
e.printStackTrace();
}finally{
try{
stdIn.close();
msocket.leaveGroup(group);
msocket.close();
}catch (IOException e){
e.printStackTrace();
}

}

}

}
---------------------------------------------------------------------------------------------------------------------------------------------
// the exception thrown by the client :

java.net.SocketException: No such device
at java.net.PlainDatagramSocketImpl.join(Native Method)
at java.net.PlainDatagramSocketImpl.join(PlainDatagramSocketImpl.java:172)
at java.net.MulticastSocket.joinGroup(MulticastSocket.java:276)
at Client.main(Client.java:27)