When you compile the two modules, with disabling the package statement, it runs on one single machine, that's running the server, but when you try to add more clients to it through a local router , it does not respond. Part of the assignment is how to detect the correct IP address and run it locally.
One activate the package chatroom.*; statement it gives a run-time error on both sides, main class not found, this is an issue that has to be resolved, too because several years ago.
After all I wish we that each client can just have an archive file of the GUI so it can run as many clients as desired.
Attachment:- JAVA_Question.zip