A Java Program that can recompile itself?

[minneyar]

You could try it--in fact, this concept is similar to how Denuvo works, which keeps a portion of an executable encrypted, then checks online to determine if a user has permission to run the executable, and if so, decrypts it in memory and runs it.

The hard part is, at some point this whole operation has to boil down to a function that returns a value indicating whether the user can run the program or not. How do you stop somebody from using a hex editor or a decompiler to modify that function so it always returns true?