"instrumentation" block can be a good place for both.
The problem is that the instrumentation code is not (easily) modularizable as it's intermixed with a bunch of places (in short, is an aspect, not an object).
I haven't looked into this yet but... Doesn't instrumentation also work through java bytecode transformation?
So having a special classloader inside an intrumenation block that transforms the classes should be enough... IMO
...or what am I here missing?
cheers -- Torsten
