@Override public void changeOnlineStatus(int id, int status) throws RemoteException { dataBaseOpeartions.changeonlineStatues(id, status); ArrayList<User> myFreiends = getContacts(id); HashMap<Integer, ClientInterface> myOnlineUser = new HashMap<>(); for (User user1 : myFreiends) { if (connectedUsers.containsKey(user1.getId())) { myOnlineUser.put(user1.getId(), connectedUsers.get(user1.getId())); } } Iterator onlineuser = myOnlineUser.keySet().iterator(); while (onlineuser.hasNext()) { Object object = onlineuser.next(); ClientInterface clients = myOnlineUser.get(object); clients.userNotificationstatues(id, status); } }