Multicast Sender and Receiver code problem

Question

Hi
I am developing a multicast chat program. I am using codes from a well known book "Java Network Programming". I have run both programs 'MulticastSniffer' and 'MulticastSender'
MulticastSniffer runs OK but MulticastSender gives me the error below:
java.lang.NumberFormatException: null
Usage: java MulticastSender multicast_address port ttl
I cant figure out the error. Could some one please help me here to find the error. I have put both programs below: Thanks
Here is the code for MulticastSniffer.java
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("235.0.0.1");
port = Integer.parseInt("8192");
} // end try
catch (Exception e) {
// 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 e) {
System.err.println(e);
finally {
if (ms != null) {
try {
ms.leaveGroup(group);
ms.close();
catch (IOException e) {}
Here is the code for MulticastSender
import java.net.*;
import java.io.*;
public class MulticastSender {
public static void main(String[] args) {
InetAddress ia = null;
int port = 4445;
byte ttl = (byte) 1;
// read the address from the command line
try {
ia = InetAddress.getByName("235.0.0.1");
port = Integer.parseInt(null,4445);
if (args.length > 2) ttl = (byte) Integer.parseInt("8192");
catch (Exception e) {
System.err.println(e);
System.err.println(
"Usage: java MulticastSender multicast_address port ttl");
System.exit(1);
byte[] data = "Here's some multicast data\r\n".getBytes();
DatagramPacket dp = new DatagramPacket(data, data.length, ia, port);
try {
MulticastSocket ms = new MulticastSocket();
for (int i = 1; i < 10; i++) {
ms.send(dp, ttl);
ms.close();
catch (SocketException se) {
System.err.println(se);
catch (IOException ie) {
System.err.println(ie);
I will appreciate your help

Answer 1

Hi kdajani thanks for reply
It doesnt give any line number or doesnt tell where the error is.
after i run the program it gives error below. if you run the program you will see what happens.
java.lang.NumberFormatException: null
Usage: java MulticastSender multicast_address port ttl
And
according to the reply from sabre150 , I have tried using
port = Integer.parseInt(null,"4445");
using above code gives the error below
MulticastSender.java:18: cannot find symbol
symbol : method parseInt(<nulltype>,java.lang.String)
location: class java.lang.Integer
port = Integer.parseInt(null,"4445");
and
port = 4445;
using this does not execute at all
They dont work either.
Thanks you all