Java RMI - RegistryImpl_Stub cannot be cast to my remote interface

Question

I'm developing a server-client program using rmi. I have 2 Rmi's Server: Primary and BacI'm trying to access RmiServer running on another machine. In my first attempts to connect the client to rmi on 2 different machines, it started to work fine, but after modifying some things in the methods of the classes, I stopped being able to connect the client to the server. I'll show you an excerpt of server and client code.

Server Side

public class RmiServer extends UnicastRemoteObject implements ConnectionRMI

//MAIN Function

try{
    if(args.length!=4){
        System.out.println("Number of arguments invalid! Rmi Server will close.");
        return;
       }
        address = InetAddress.getByName(args[0]);
        portUdp = Integer.parseInt(args[1]);
        otherPort = Integer.parseInt(args[2]);
        otherAddress = InetAddress.getByName(args[3]);
        Registry registry = LocateRegistry.getRegistry(otherAddress.getHostAddress(), 1099);
                registry.lookup("RmiServer1");
                System.out.println("[INFO]: Backup Server RMI is ready! ");
                primary = false;
            } catch (NotBoundException | RemoteException ex) {
                primary = true;
                try {
                    Registry registry = LocateRegistry.createRegistry(1099);
                    registry.rebind("RmiServer1", registry);
                } catch (RemoteException ex1) {
                    System.out.println("The registry in port 1099 is already created. The program will close\n");
                    return;
                }
                System.out.println("[INFO]: Primary Server RMI is ready! ");

            } catch (UnknownHostException ex) {
                Logger.getLogger(RmiServer.class.getName()).log(Level.SEVERE, null, ex);
            }

Interface ConnectionRMI

public interface ConnectionRMI extends Remote{
}

Client Side

try{
            address1 = InetAddress.getByName(args[2]);
            address2 = InetAddress.getByName(args[3]);
            registry = LocateRegistry.getRegistry(address1.getHostAddress(), 1099);
            atualRmi = (ConnectionRMI) registry.lookup("RmiServer1");
            server1 = true;
        }

The error is in this line:

atualRmi = (ConnectionRMI) registry.lookup("RmiServer1");

Error:

Exception in thread "main" java.lang.ClassCastException: sun.rmi.registry.RegistryImpl_Stub cannot be cast to sdeleicoes.ConnectionRMI

Answer 1

registry.bind("RmiServer1", registry);

The problem is here. You are binding the Registry into itself. This makes no sense. You should be binding one of your remote objects.