I need a simple open source Java game to assign it as a programming task to my friend who is learning Java and to be as a reference for him while re-implementing it. He wants to get his hands dirty with a real project but he is still in his first steps in learning the language so don't expect him to make a big game :)
EDIT: the game doesn't matter to be a console based game or a gui game. All what I need is giving him a good programming practice.
Have a look at Robocode or Greenfoot.
I think Greenfoot is better and nicer for learning Java. Learning should be fun otherwise your friend has to fight with simple things (ide, building problems, etc.) which are killing the fun.
how about tic tac toe. Thats what we learned in VB class way back in the day, it has drawing needs, logic needs and is simple and universally understandable how to play.