You seem to be describing things that frameworks like Spring add. Java itself (as a language) doesn't "do" anything with annotations, they are literally just so

You seem to be describing things that frameworks like Spring add. Java itself (as a language) doesn't "do" anything with annotations, they are literally just some extra strings in the class-file. Spring and its friends use those strings to do their magic. (Personally I find modern Spring applications as inscrutable as RoR applications which does indeed throw many categories of debugging out the window. Can't set a breakpoint if you have no idea what bootstraps what.)