Java Instant Messenger

Java Instant Messenger Needs to be as simple as possible. Required Features: - multithreaded - multi-platform - Login with password / New User (details can be stored in a text document) - Contact list (ability to add friends and see which friends are online) - private chat (between 2 persons) - group chat (between more than 2 persons) - FTP between users I have some started code already, which I would ask that you modify. No plagiarism of code from another source. Any borrowed code should be referenced as this project will be highly scrutinised. All code should be heavily commented, so that I may learn from it. Keep as simple as possible.