Hello,

I don't think that there is a possibility to encrypt the jar file so
that the Java VM still can deal with it. Unless you would use your own
classloader which decrypts the jar files before loading classes from it.
This class loader must be located outside of your encrypted jar file of
course.

What you could do is use an obfuscator (google will help ;-), which
renames your variable and method names to a, b, c, d(), e(), f() and so
on, which makes it hard for anybody who decompiles your classes to read
the code.

Regards,
Stefan

Think for a second what you have asked. If nobody can decompress or
decompile it, how can anybody RUN it?

If you can run it, then you must have given the keys to run it to some
piece of software to decrypt it.  It now becomes possible to repeat
that, at least in theory.

See http://mindprod.com/jgloss/obfuscator.html

I tackle this problem in my dark room essay.  See
http://mindprod.com/jgloss/darkroom.html

However, my scheme requires special hardware that does not exist on
the open market.

Retroguard is a good obfuscator.