[SOLVED] Network Programming Using Datagrams

[IandI]

Hello Coders,

I'm trying to write a simple application with two programs running on different computers on the same network. The idea is to send a string of text to one machine which then replies with another. I having trouble getting it to work despite serious reviews/investigation.

What I've done to try and rectify the problem
1. I noticed some activity with the firewall when trying to run the program and decided to disable the firewall on both computers with no luck.
2. I used the net view command which shows both the computers.
3. I can also ping them both
4. I've gone over the code a number of times - and suspect/convinced the
issue lies within it.
5. I kindly request your assistance

import java.net.*;

public class myServer {
//send a message to another computer via datagram
	public static void main(String []args) {
		
	try
	{
		String hostname = "vista";
		InetAddress address = InetAddress.getByName(hostname);
		int port = 1234;
		String message = "Who am I";
		byte[] data = message.getBytes();
		DatagramSocket s = new DatagramSocket();
		DatagramPacket p = new  DatagramPacket(data,data.length,address,port);
		s.send(p);
		System.out.println("Packet sent2");
		s.close();
	}
	catch(UnknownHostException e)
	{
		System.exit(0);
	}
	catch(SocketException f)
	{
		System.exit(0);
	}
	catch(java.io.IOException g)
	{
		System.exit(0);
	}
	}
}

The receiving station code

	import java.net.*;
	import java.io.*;
	import java.lang.String.*;
	
	public class myClient {
	public static void main(String args[]) 
	{
		try	
		{
		byte[] buffer = new byte[4096];  //to contain bytes in the datagram packet.
		DatagramSocket s = new DatagramSocket(1234);  //create socket to recieve & send datagrams.
		DatagramPacket p = new DatagramPacket(buffer,buffer.length);
		s.receive(p);
		String msg = new String(buffer,0,p.getLength());
		s.close();
		}
		
		
			catch(SocketException e)  //Exception Handler
			{
				System.exit(0); //clean up 
			}
			catch(java.io.IOException e)  //Exception Handler
			{
				System.exit(0); //clean up
			}	
	}
	}

[CJSLMAN]

I tried the code and it worked OK if I replaced the variable hostname with "localhost" since I was running on the same computer. Without that change, I was seeing that myServer was finishing and myClient was still waiting to receive data. So, is the host name "vista" correct?

Luck,
CJSL

[IandI]

I tried the code and it worked OK if I replaced the variable hostname with "localhost" since I was running on the same computer. Without that change, I was seeing that myServer was finishing and myClient was still waiting to receive data. So, is the host name "vista" correct?

Luck,
CJSL

Thanks for the replying.
I still seem to have issues. I tried following your suggestions and running it on the same computer but myClient was still waiting to receive data. Using the same computer, I tried a couple of things

1. I replaced the variable hostname with "localhost"

String hostname = "LocalHost";  //tried both for case sensitive sake
		InetAddress address = InetAddress.getByName(hostname);

2. I also tried it by removing the variable "hostname" altogether and using the "getLocalHost" instead.

	InetAddress address = InetAddress.getLocalHost();

Both attempts as you said leave myclient hanging.

"So, is the host name "vista" correct?" It is

Where am I going wrong? Thanks

[CJSLMAN]

Sorry about that... there's another thing that I did... I replaced the following in myClient:

String msg = new String(buffer,0,p.getLength());

For this:

String msg = new String(p.getData());

Sorry about that... I forgot about that change...

Luck,
CJSL

[IandI]

Sorry about that... there's another thing that I did... I replaced the following in myClient:

String msg = new String(buffer,0,p.getLength());

For this:

String msg = new String(p.getData());

Sorry about that... I forgot about that change...

Luck,
CJSL

Thanks again....but "myclient" still seem to hang.