Decompiler :(

[Siva Jagadeesan]

Dear All :
I have a s/w written fully in Java . I was shocked to see JAD( java decomiplers ) So is there anyway I can protect my source code ??!?!?! is there any I can scramble the code so no one can decompile it .
Thanx
Siva

[James Nuzzi]

You can protect your code with code obfuscation. This basically "scrambles" the code. This does not, however, completely protect your code from decompilation. It only makes it harder. Also, there may be some side-effects to obfuscating your code, like performance issues.

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James Nuzzi
SCJP, SCJD, SCWCD

[Jorge Phillips]

Yes. Obfuscation will make it very difficult to decipher the decompiled java classes. But it does not necessarily penalize performance. The JVM couldn't care less about what your names look like. But it does care about the size of the load stream.
Check Dash-O by Preemptive Solutions (www.preemptive.com). Not only do you get very good obfuscation but a reduction in compiled class size reduction of up to 70% and a substantial performance improvement (they claim 30%).
[This message has been edited by Jorge Phillips (edited September 27, 2001).]

[Johannes de Jong]

You might want to look at this as well Your complete guide to the decompilation and obfuscation of Java code by Greg Travis on the IBM DeveloperWorks site.

[Siva Jagadeesan]

Dear All:
Thank you for ur suggestions .. I will surely look into them
Thanx
Siva

[David Weitzman]

Originally posted by Jorge Phillips:
Yes. Obfuscation will make it very difficult to decipher the decompiled java classes. But it does not necessarily penalize performance. The JVM couldn't care less about what your names look like. But it does care about the size of the load stream.
Check Dash-O by Preemptive Solutions (www.preemptive.com). Not only do you get very good obfuscation but a reduction in compiled class size reduction of up to 70% and a substantial performance improvement (they claim 30%).
[This message has been edited by Jorge Phillips (edited September 27, 2001).]

It is true that mediocre obsfucators are likely to improve both performance and size, but a good one may cost either. Simply changing method and class names provides ok protection, but the people at http://www.zelix.com/klassmaster/index.html are proud to outdo the competetors with real flow obsfucation.