CGLIB is distributed in binary and source form

cglib-2.1_x.jar             binary distribution, CGLIB classes only,
it must be used to extend cglib classes dependant on ASM API

cglib-nodep-2.1_x.jar       binary distribution, CGLIB and renamed ASM classes,
not extendable

cglib-src-2.1_x.jar         source distribution with all runtime dependancies

cglib-docs-2.1_x.jar        HTML API documentation

Use Apache Ant to build CGLIB from source code : http://jakarta.apache.org/ant