does anybody has some thread on icq's design ?

I want to make a chat sw like icq!
only for strengthen the knowledge about javax.swing,javax.io,and java.net!!
i konw swing is the lagest package in java,and java.net and java.io are very important in java's net programing,so i want to master them as i can!!

For an intro to Instant Messaging, have a look at the article at HowStuffWorks here, which also includes info on ICQ.
Dave