I recall Intellij Idea IDE had some pretty decent protection. They used an "encrypting" class loader (of the xor variety), and also encrypted all their resource

I recall Intellij Idea IDE had some pretty decent protection. They used an "encrypting" class loader (of the xor variety), and also encrypted all their resource files. I have a lot of respect for the lengths they went to, though i'm not sure how much it benefitted them really.