GF4J is a very easy to use Library GNU licensed open source 2D game programming library for Java. If you are like me, a hobbyist writing games and you want to get started as fast as possible you should give GF4J a try.
Users can write their own effects.
Easily customizable bitmap font support for 256 character fonts. Gridder - The Level Editor Gridder is an easy to use, GNU licensed open source level editor for editing grid based levels.