Chesspresso™ is Java library to help developers in writing any kind of chess program. It is open-source (LGPL) and contains state-of the art algorithms to implement chess concepts.
When you always wanted to write a chess application but feared the effort to implement all the necessary data structures and rules, Chesspresso™ is the just what you might be looking for. Chesspresso™ wants to be the library you base your next Java chess-program on. It is prepared to a base for all kinds of chess applications, be it databases, game browsers, statistic programs, engines, front-end for internet chess servers, teaching programs, etc.
Chesspresso™ was actually not only a chess library, but a full database program . Feel free to download that version as well (not open-source). Recently, I decided to make the core of the application open-source and call it Chesspresso™ as well. I have not decided yet how to resolve that confusion.