It's a really good subject in my opinion and for me the communication between program is very useful and teach me the basic concept. Depending on your expertise, programming in Java can be extremely difficult, ESPECIALLY if you use the IDE that they recommended, BlueJ. That thing can and will frustrates you. If you go down in the programming path, I recommend you using Eclipse. Other than the programming, it has been fun for me.

A tough unit if you haven't done much networking, and you're unlikely to do much further development on the networking level that this subject teaches you, but it gives a decent background to the way networking works on a very low level. There's quite a bit of programming that involves sending bytes from one computer to another.