@Override
        public void run() {
          ObjectOutputStream output;
          UserCameOnlineMessage message = new UserCameOnlineMessage(usernameThatCameOnline);
          for (User it : onlineFriends) {
            try {
              output = it.getConnection().getOutputStream();
              output.writeObject(message);
              output.flush();
            }
            catch (IOException e) {
            }
          }
        }