Modify a method using Annotations

Question

How can I change what a method is doing in Java ?

I mean, I am trying to use annotations to make the following code

@Anno1(Argument = \"Option1\")
p         


        

Answer 1

It's perfectly possible to do what you ask, although there is a caveat: relying on private compiler APIs. Sounds scary, but it isn't really (compiler implementations tend to be stable).

There's a paper that explains the procedure: The Hacker's Guide to Javac.

Notably, this is used by Project Lombok to provide automatic getter/setter generation (amongst other things). The following article explains how it does it, basically re-iterating what is said the aforementioned paper.