I know some program which transforms a .class into a PE executable. But is there a program which allow to recover the .class from the .exe ?
Thanks

you can try this: http://www.multimania.com/dolmen/productions/j++extract.zip

as http://www.multimania.com/dolmen/productions/index.shtml states:
J++Extract 1.0: J++Extract.zip ( 22k, 30/07/2000, English)
This command line tool for Windows extracts Java class files from a .exe created with Microsoft Visual J++.
License: GPL.