Just spotted the new JDK1.5 early-access compiler.
This release adds support for the new JSR201 features (new "for each" loop, autoboxing, etc.).
It also adds experimental "variance" support to Generics (this is not part of JSR14, it's just an experiment). Adding variance support to Generics solves some nitty-gritty annoyances in JSR14... but oh boy... if you thought Generics was complicated to begin with then this will blow your mind!
If you want a quick run-down, read the "variance-overview.pdf" presentation contained in the early-access download. I'll digest it some more and add some comments in the coming days.