So I installed the Java addon. But where is it?

Nah, the wheel definitely hasn't been reinvented. It's still configure - make - make install, basically. It's just that most of the current distros have their own way of wrapping things. And since the ReadyNAS is built on Debian, it makes sense to build packages their we - and be it only because they're a lot easier to remove and upgrade using the dpkg system. Well, at least I find it to be a lot easier, others may have a different opinion there.

-Stefan