Jdec is a java decompiler which currently supports
classes compiled using java compiler from SUN Microsystems LTD
Jdec has been tested mainly on 1.4.x release from SUN.However
Jdec will attempt to decompile 1.5.x

[ Classes compiled using 1.5.x but having features of < 1.5.x should get decompiled.]

Please check-up the roadmap and features for more details.