This is a very light version chatting tool, programmed in JAVA. However it supports a lot of important and useful features, like, constantly update online user list, and broadcast message to multiple users.
1. new user came online
2.online user disconnected
3.Single target communication
4.Multiple targets communication
finally fix the bug of Jlist rendering, the solution is using swingutility.invokelater method to undate UI whenever an update is ready and required, this will guarantee all UI rendering is in Event Dispatch thread. other than this fix, the rest are just fine.