LITIengine is a free, open source and easy to learn 2D Java Game Library. It provides the infrastructure to create a 2D tile-based Java Game, be it a platformer, a top-down shooter or an RPG. The main features include a 2D Physics Engine, a 2D Render Engine, a 2D Sound Engine, a Particle System, support for Tiled Maps (.tmx) and a clean API for the Basic Game Infrastructure. LITIengine is invented, written and maintained by the two bavarian brothers Steffen and Matthias and it has become a considerably popular open source project with a rising number of contributors and an active Community.
One major difference to other engines is that the 2D Render Engine is entirely based on plain Java AWT Graphics. If you've learned or starting to learn Java this will instantly give you great results and highly optimized rendering performance with what you already know. We think that this is a great and simple way to start making video games without having to care about a lot of vector math or "OpenGL shenanigans". The graphics can then be further enhanced by the Particle System to create beautiful visual effects (like fire or smoke). There is only a bare minimum of third party libraries included in LITIengine, which we want to mention here thankfully:
JInput for Gamepad support
MP3 SPI for .mp3 audio file support
Ogg Vorbis SPI for .ogg audio file support
Steamworks4j for supporting the steamworks SDK
Environments in the LITIengine are based on
.tmx tile maps which can be created and edited with the well known Tiled Level Editor and brought to life with LITIengine entities.
SoundEngine supports two dimensional audio that can be played relatively to a position in the environment.