libGDX
Desktop/Android/HTML5/iOS Java game development framework
.... libGDX comes with batteries included. Write 2D or 3D games and let libGDX worry about low-level details. Heavy emphasis is put on avoiding garbage collection for ART/JavaScript by careful API design and the use of custom collections. libGDX is a well proven and reliable framework with a sound base and documentation. Furthermore, there are plenty of games built on top of libGDX, many of which are open source.