Yes, I did spend large parts of my java developer looking at class loaders and class loading delegations in servlet containers etc.

I think it's a bit too hard to get it right.

Like, suddenly some third party library starts pulling in log4j and your whole logging setup goes wrong in subtle yet very bad ways.

Or you screwed up with that one reference to a ResultSet and even though it is closed, that reference keeps an entire class tree of Connection, PreparedStatement etc alive.