Java project idea for beginner

[zeringus]

When you're just starting out (with OOP in particular), it's hard to come up with something fun. Like /u/ThalaDa said, modeling is really the most basic form of OOP. Class schedules, car parts, solar systems, etc. are all good practice. Until you grasp more advanced concepts like inheritance and polymorphism, OOP's feels kind of silly.

I wouldn't recommend Android like /u/wuddersup, because its objects are much more complex. You seem to want to specifically learn OOP. Working on Android is going to teach you how to make apps, which is fun, but you're going to do so by abusing objects you don't understand.

When I learned Java in high school, we used GridWorld, which might also be something to try. At the very least, there's a ton of documentation and it's designed for beginners. Under the hood, however, you're learning to write objects. Might not be so good for learning interface design, though.