dear all I am developing a small program based on JAVA No UI but RUN It is used to monitor websocket specific packets (get game items at a specific time) When a specific packet is monitored, it will be notified But this packet has Features of the countdown timer After receiving, update the next countdown time approximately every 3 seconds (because of the delay characteristics of network packets and the characteristics of website traffic) I am currently experiencing some problems When I receive the packet and start the countdown with thread In the end, I didn't specify the time or pass something!! Because the time is late!! It may be too early Because of the aforementioned delay characteristics and other reasons Plus other people use (multiple simulators with simulated click to get) So the time I got it was late compared to others!! But it is also possible Because the game item was not distributed on the server, I got the result ok but it was empty item!! So I am early!! How can this be solved?