Pass by reference problem in RMI? [duplicate]

Answer 1

your question is not clear enough but:

debug your code, or put some logs (simply System.out.println) before the line that you are getting NPE. maybe you List is still null.

public void updateClients() throws RemoteException {
    **if (serverList != null) {**
        for (TTTClientRemote aClient : serverList) {
           aClient.updateClients("slam");
        }
    }
}