Java source files security

using decompiler we can decompile the Java file.how to avoid that?How can i make class files more secure?

Please guys help me out!!

Try "I'm feeling lucky" on Google with "prevent decompilation java class" as search terms. The article there gives a precise description of the problem you are facing.

This is done in part with what is called an obfusicator, there are plenty of them and will show up on a google search. DRM is worthless for the most part, hide in plain sight - but protecting a customer's information is another matter, to which you have a duty.

That is done with crypto, most businesses do not have the time or will to deal with someone who has to decompile a java class file to get code. It is just not worth the effort, standard business practices of customer should be able to keep their work in house.