Registry registry = LocateRegistry.getRegistry("localhost", 11701);

try { // подключение к серверу
    Registry registry = LocateRegistry.getRegistry("localhost", 11701);
    service = (IRemoteServer) registry.lookup("remiss");
} catch (Exception e) {
    e.printStackTrace();
}

try { // вызов функции
    status = service.tryJoin("login","password");
} catch (Exception e) {
    e.printStackTrace();
    status = "fail";
}