An object-oriented implementation inspired by "How to Design Classes" The interesting part is the decomposition of the elements in the game and the Double Buffer Strategy implementation, which is when you know it fairly simple. It lacks an Input-System from the user, which can be easily implemented, by adding a method for UFOWorld which will pass the Key Event on to the Player/AUP and it will handle the correct update.
kaiserprogrammer/SimpleJavaGame
An Object-oriented Java Game with BufferStrategy (Proof cof Concept)
Java