Flux Chess is an attempt to write a computer chess engine entirely in Java. The speed of most Java Virtual Machines is improving nowadays. However compared to other C/C++ chess engines Flux is still slow (or maybe my algorithms are not that sophisticated?).
As a pure UCI chess engine, Flux does not have a graphical user interface. You can load him however into your favorite chess program if it supports the UCI protocol.
Flux Chess is released under version 3 of the LGPL.