RMI lookup, NoSuchObjectException

Question

Hello!
I have a problem with RMI. And I hope someone is able to help me!
I have a running Server, wich opens a UnicastRemoteObject and binds it to the registry.
My client is running in a NSI CrEme VM. The clients connects to the regitry via lookup.
My Problem case: If the device is turn off and then turned on again (On Windows CE the app is still running), the network connection was lost for a little time. So the RMI connection could not send the least signals any more (So after the set least time... the connection expired). So the objects are not available any more and on a call of the remote object a RemoteException occurs.
What I do then is, I connect the remote object again via lookup. This works, but now each call on the remote object takes a long time to proceed.
So I turned on the log calls from RMI on the server... and they say, that there is a NoSuchObjectException is thrown. But I am wondering why after a little time the call on the remote object is successfull. Each call now takes time, because each time it is trying to find the object and says, that it's not found. Anyway the call is successful.
If I restart the app, all works fine... but what I want is to reconnect without restarting the app.
What can I do? The thing I want to do is to "reconnect" without starting the VM again after the least time is expired. To lookup won't work. Or am I doing anything wrong?
Thanks for your answers!
Yves

Answer 1

Hello!
What I have just done was to make the server stub as static.
My code, whicht does it:
LocateRegistry.createRegistry(MyServer.getRMIPort());
serverInterface = (MyServerInterface)UnicastRemoteObject.exportObject(server, MyServer.getUnicastRemotePort());
Naming.bind("rmi://localhost:" + MyServer.getRMIPort() +  "/myServer", serverInterface);
public SessionInterface getSession(String userName, String clientName,
          Locale locale) throws ClassNotFoundException,
          IllegalAccessException, InstantiationException, RemoteException {
     logger.info("User " + userName + "@" + clientName + " tried to connect.");
     SessionInterface session = new Session();
     return (SessionInterface) UnicastRemoteObject.toStub(session);
}And my client reconizes the NoSuchObjectException and then does a reconnect via a new lookup.
Client-Code:
try {
     instance.getRMISession().isAlive();
     System.out.println("ALIVE");
} catch (RemoteException ex) {
     System.out.println("REMOTE EXCEPTION");
     instance = null;
     System.gc();
     instance = new RMIConnector(MyClient.getInstance()
                    .getHostconnectionData().getIpAdress(),
                         MyClient.getInstance().getHostconnectionData()
                              .getPort());
     instance.tryLookup(); // HERE IS DONE A NEW LOOKUP - WHICH JUST WORKS FINE!!!
}And the code which gives me the class from the factory:
if (session == null) {
     if (!connected)     {
          this.tryLookup();
     System.out.println("RMI: getting Session Object.");
     session = server.getSession(ClientConnectionData.getInstance()
                    .getLoginData().getLogInName(), ClientConnectionData
                         .getInstance().getHostNameIpAdress(), null);
     // we must resend the logindata any time we connect to host
     sendLoginData();
connected = true;
return session;After this the connection works, just with the situation explained above. (First post)
The NoSuchObjectException now is not thrown to the client. I just see the Exception if I turn on the logs and exceptions for RMI on the server.
There I get the following message:
Feb 27, 2009 9:38:35 AM sun.rmi.transport.Transport serviceCall
FINE: RMI TCP Connection(49)-10.28.17.20: [10.28.17.20] exception:
java.rmi.NoSuchObjectException: no such object in table
        at sun.rmi.transport.Transport.serviceCall(Transport.java:129)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:4
66)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport
.java:707)
        at java.lang.Thread.run(Thread.java:595)The intresting thing is, all just works fine, each call on the functions and the return values... BUT every time it takes a long period to proceed (about 10seconds). What I also can see in the RMI loggings on the server, ist that first the function is executed and after this it says a few times the NoSuchObjectException exception before the Client goes on.
I hope you can help me!!!
Yves