jclasslib is released under the GPL.

OS	Downloads
Windows	Setup Executable ZIP Archive
Supported versions: Vista/7, Server 2008, Server 2003, 2000/XP, NT.4.0, 98/ME
Mac OS X	SIT Archive
Supported architectures: Intel, PPC Supported versions: 10.6, 10.5, 10.4, 10.3
Linux / Unix	TAR.GZ Archive RPM

Older version of jclasslib are available from the Sourceforge project page.