protecting source?

[sde]

i have a friend who is working on a java project and asked me if there was anyway to protect the source of the applicaition from being viewed or decompiled?

are there any tools like this for java?

[joe_bruin]

sure: don't give the source or compiled version to ANYBODY. in fact, delete it, wipe the hard drive, and then melt it.

[Belisarius]

".class" files can be easily decompiled, and there's no way around that.

There are programs that turn Java into machine-executable code (same as C code). This breaks portability, and of course the compilers will usually lag behind the JVM in Java compatability, but they exist. See gcj.

[sde]

thanks Be, .. i'll pass the info along! i really appreciate it!

[technobard]

Well, nothing is foolproof, but there are java obfuscators that make it very difficult to decompile to source. Do a google on "java obfuscator" and you'll get a number of hits.

[Belisarius]

If I recall correctly, obfuscators don't affect decompilation so much as readability. You can decompile the class files just as easily as non-obfuscated class files, it's just that what you end up with is very hard to work with.

[technobard]

Yeah, I think you're right. At least one that I'm aware of creates a numeric substitution list and displays numbers for major portions of the source code when you decompile. So the source you get isn't true source although with the same obfuscator you can replace the substitutions with the original values to get true source again. It's something that will probably stop all but the most determined individual.

[Hrqls]

does anyone know of any nice free tools to decompile a java class ?

[Belisarius]

http://www.sureshotsoftware.com/jcavaj/index.html
http://www.kpdus.com/jad.html
http://members.fortunecity.com/neshkov/dj.html

That's just from googling though . . .

[Hrqls]

thanks .. guess i will try some

i found a whole list of them .. was wondering if there some who were much better than the rest

[Rotkiv]

just for the record, DJjava worked very well for me, and it makes it way too easy to get the source code for a java .class.

[Hrqls]

ah thanks .. that will be the first me to try

will also experiment with a few obfusticators (sp?) and have a look at their results