Passing a remote client interface to a remote server

Here is the environment:

I have a remote coordinator interface and a remote client interface which implement Remote interface:

Code:

---

public interface CoordinatorInterface extends Remote {

        public void test() throws java.rmi.RemoteException;
        /**
        * remote function used by client to connect
        */
        public void connectClient(ClientInterface clientInterface) throws java.rmi.RemoteException;
}

---

Code:

---

public interface ClientInterface extends Remote {
       
        /**
        * create a client interface
        */
        public void updateClientList() throws java.rmi.RemoteException;
       
        /**
        * update client's whiteboard
        */
        public void updateClient() throws java.rmi.RemoteException;

}

---

And a NetworkCoordinator class implements the CoordinatorInterface; a NetworkClient class implements that ClientInterface:

Code:

---

public class NetworkCoordinator implements CoordinatorInterface{

        private static final long serialVersionUID = 1L;
        /**contains client id and client interface*/
        private Hashtable clients;
        /**contains the request the server processed*/
        private Hashtable requests;
        /**clientId counted by Server*/
        private long clientIdServer;
        /**sequenceId counted by Server*/
        private long seqIdServer;
       

        public NetworkCoordinator() {
                super();
                clients = new Hashtable();
                requests = new Hashtable();
                clientIdServer = 1000;
                seqIdServer = 1100;
        }

        public void test() throws java.rmi.RemoteException
        {
                System.out.println("test");
        }
        /**
        * remote function used by client to connect
        */
        public void connectClient(ClientInterface clientInterface) throws java.rmi.RemoteException
        {
                clientIdServer++;
                clients.put(clientIdServer, clientInterface);
                //put keys into enumeration
                Enumeration clientsEnum = clients.keys();
                //update each client's clientlist
                while(clientsEnum.hasMoreElements())
                {
                        int clientId = (Integer)clientsEnum.nextElement();
                        ClientInterface ci = (ClientInterface)clients.get(clientId);
                        ci.updateClientList();
                }
                System.out.println("Client connected");
        }
       
        public static void main(String args[])//this is going to be run()
        {
                if (System.getSecurityManager() == null) {
                        System.setSecurityManager(new SecurityManager());
                }
                try {
                        //the name for client to look for in registry
                        String name = "Coordinator";
                        NetworkCoordinator testServer = new NetworkCoordinator();
                        CoordinatorInterface stub = (CoordinatorInterface) UnicastRemoteObject.exportObject(testServer, 0);
                        Registry registry = LocateRegistry.getRegistry();
                        registry.rebind(name, stub);
                        System.out.println("Coordinator bound");
                } catch (Exception e) {
                        System.err.println("Coordinator exception:");
                        e.printStackTrace();
                }
        }
       
}

---

Code:

---

public class NetworkClient implements ClientInterface {

        /**
        * create a client interface
        */
        public NetworkClient() {
                super();
        }
       
        /**
        * update client's list of nodes
        */
        public void updateClientList() throws java.rmi.RemoteException
        {
                System.out.println("updateClientList called by server.");
        }
       
        /**
        * update client's whiteboard
        */
        public void updateClient()throws java.rmi.RemoteException
        {
               
        }

        /**
        * for test using
        * @param args
        */
        public static void main(String[] args) {
                if (System.getSecurityManager() == null) {
                        System.setSecurityManager(new SecurityManager());
                }
                try {
                        String name = "Coordinator";
                        Registry registry = LocateRegistry.getRegistry(args[0]);
                        CoordinatorInterface serverinterface = (CoordinatorInterface) registry.lookup(name);
                        NetworkClient client = new NetworkClient();
                        ClientInterface stub = (ClientInterface)UnicastRemoteObject.exportObject(client,1);
                        serverinterface.connectClient(stub);
                        //UnicastRemoteObject.exportObject(client);
                        //serverinterface.connectClient(client);
                        serverinterface.test();

                } catch (Exception e) {
                        System.err.println("Client exception:");
                        e.printStackTrace();
                }
        }
}

---

My goal is to start the coordiantor and client, and then the client will use serverinterface.connectClient(stub);
to pass its interface to the coordinator, and the coordinator will save it into a hashtable and call client's updateClientList() method.

The Coordinator class runs fine, I can get to the "Coordinator bound" system output. And the serverinterface.test() call works too. But my problem is how to pass the clientinterface to the coordinator, by using serverinterface.connectClient(clientinterface); In the above code I would get a Client exception:
Java.rmi.StubNotFoundException
What did I do wrong?

Thanks a lot
J.

Problem solved.
long to int casting problem...
How stupid I am
Please ignore this thread