If you have a lot of movies or books, you could make an application that would keep track of them for you. You could keep track of movies you own, movies you've seen, movies to never watch again.... you could keep the mini databases in simple text files to get started.... this is a pretty complicated project, but making it would require lots of necessary skills and be satisfying if you need something like it. Obviously, as you start out you'd be making little pieces that work, then fit them together (that's the fun of object oriented programming).
The book HeadFirst Java (the best textbook I have ever purchased) has instructions on how to make a battleship style game and a MIDI music player... I've been having fun with both (and learning too!)
I'm a contract employee, so I've been thinking about making an app that keeps track of my hours, projects, invoices and how much I'm owed.
You could make a gratuity calculator (not like you'd take your laptop to dinner, but it's the concept)...
The list of games is endless... hangman, trivia games.... there's this game "nibbles" for VBasic, I dunno how hard it would be to recreate in Java.... strategy games...
You could do pretty much anything.
Janeice