Serializing is a sensible choice if you want something really simple that should always work.

It works by using the DataOutputStream/DataInputStream classes (in java.io I believe), and making some arbitrary 'message' class that implements Serializable.  

Then you can do something like outputstream.write(object) on one end, and Object o = inputstream.read() on the other end.

Just build that object with whatever members you want to send across (such as your matrix), setup the streams (with sockets and socketserver), then do the appropriate casting, try/catch blocks and be on your way.

Your other choice is to use some other input/output stream method and handle data read/write yourself, which is probably not worth the effort for however many bytes you may send.  If it's in a local network, you wouldn't even notice at 4~10 times per second.

Marcello

that actually sounds like myObjectReader itself is null, or that something inside myObjectReader is null (connection no good or something like that). because otherwise, your code should be fine.

You were right, Fry. It looks like I forgot to instantiate the object reader.

Now that I am instantiating the object reader, my program hangs on that line.

Here's the source:

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

public class TelemetryClient {
private SocketmySocket;
private BufferedInputStream myBIS;
private ObjectInputStream myOR;

private CubbyHole myCH;

private boolean debug = true;

public static void main(String[] args) {
new TelemetryClient("localhost");
}

TelemetryClient(String IP) {

myCH = new CubbyHole();
try {
mySocket = new Socket(IP, 4444);
myBIS = new BufferedInputStream(mySocket.getInputStream());
println("buffered input stream ok");
myOR  = new ObjectInputStream(myBIS);
println("object input stream ok");
} catch (UnknownHostException e) {
System.err.println("Error!");
System.exit(1);
} catch (IOException e ) {
System.err.println("IOException!");
System.exit(1);
}

new ReceiveThread().start();
}

public CubbyHole getCubbyHole() {
return myCH;
}

class ReceiveThread extends Thread {
public void run() {
while(true) {
try {
int[][] data = (int[][]) myOR.readObject();
myCH.put(data);
if (data[3][3] == -1234)
break;
} catch (ClassNotFoundException e) {
System.err.println("Unknown Class Exception!");
} catch (IOException e) {
System.err.println("IOException!");
}
}

}
}

private void println(String message) {
if (debug)
System.out.println("Client says: " + message);
}

}

the problem seems to be with the line "myOR  = new ObjectInputStream(myBIS);" because the println() immediately above prints, and immediately below fails. It's not throwing an exception, just freezing..

I'm sorry for asking all the silly questions but I haven't worked with sockets before, and I'm in a wee bit over my head..

Ryan