Is it possible to inherit a final class modifying bytecode somehow?

Question

Is it possible to inherit a final class using bytecode manipulations?

Answer 1

Yes and no.

You can use bytecode manipulation to change a final class to non-final on the fly. This doesn't even break binary compatibility, so there is no risk of class loader / verifier errors.

However, you have to apply the bytecode modifications to the final class itself. You can't do bytecode manipulation on a child class to make it inherit from a final parent class. Or more precisely, if you do that the modified child class will be rejected by the verifier when loaded together with the final parent class.