Simple RMI problem

Question

I am trying to set up a client server RMI connection, but i get the following error when running the server. I am new to using RMI so any help would be great, thanks so much,
Fred
Exception in thread "main" java.lang.ClassCastExcepti
cast to IMServer
at OutwardFacing.main(OutwardFacing.java:14)
here is my code:
import java.rmi.*;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
public class OutwardFacing {
     public static void main(String[] args)
     //get the remote object from the registry
          try
     String url = "//localhost/server1";
**14**     IMServer server1 = (IMServer)Naming.lookup(url);
     System.out.println("Got remote object");
     server1.Register("fred", "password");
     server1.ListRegistered();
     catch (RemoteException exc)
     System.out.println("Error in lookup: " + exc.toString());
     catch (java.net.MalformedURLException exc)
     System.out.println("Malformed URL: " + exc.toString());
     catch (java.rmi.NotBoundException exc)
     System.out.println("NotBound: " + exc.toString());
}

Answer 1

Cast the object you're looking up to the remote interface it implements, not to the type of the implementation class.