chess4j is a Java based chess program. It is not meant to be a competitive program. Its purpose is to serve as a test bed for various interests, including parallel and distributed computing, machine learning, and exploring different JVM languages and technologies.
The latest version of chess4j is v3.5. I am no longer providing download links directly from this page. You can download the source code as well as the release bundle from the chess4j Github repo:
chess4j is distributed under the MIT license. See LICENSE.TXT in the download for details, but essentially it means you can do pretty much anything you want with chess4j as long as (1) you don’t hold me liable, and (2) you provide attribution back to me.