Strange behaviour: two servers on the same port

Question

Hi!
I hope this is the right section for this post. I need help about a strange behaviour involving a ServerSocket.
For my thesis I need to write a program that receives data from a pre-existing DSMS client, filters them and then sends them to a pre-existing DSMS server. And here is my problem: if I try to create a ServerSocket on the same port of the DSMS server, my program throws no exception, and the servers seem running on the same port. This is a behaviour that I'd like to avoid, but I cannot understand what the problem is. Can you help me?
The source code of the DSMS server can be found here (it's written in C++): http://infolab.stanford.edu/stream/code/stream-0.6.0.tar.gz
The source code of my server class, instead, is this one:
import java.io.*;
import java.net.*;
public class ThreadGenerator {
     private ServerSocket server;
     public void connect(String servPort, String cHost, String cPort) {
          try {
               server = new ServerSocket(servPort);
               System.out.println("SERVER running on port "+servPort);
          } catch (BindException e) {
               System.out.println("Address already in use!");
          } catch (Exception e) {
               System.err.println(e);
          try {
               while(true){
                    Socket client = server.accept();
                    StreamThread T = new StreamThread(client, cHost, cPort);
                    T.start();
          } catch (EOFException e) {
               System.out.println("Server closed connection!");
          } catch (Exception e) {
               System.err.println(e);
}I'm programming on Mac OSX Tiger, with Java 1.5.0.
Thanks in advance for your help.

Answer 1

The problem is still happening to me, I tried in this very moment. The code I'm using is the one I posted, and the second server is the one that I linked. I don't think there's anything else to add.
If you're sure that the problem is not in my code, then it means that it is in the linked server, which partially solves the problem. But I'd like to know, if it's possibile, if there is any other way to check if the port is already in use.