Thanks to Nascif Abousalh Neto for updating the PMD Emacs plugin! Here's the big change:
So now all the rulesets are available in Emacs. It should work fine with PMD 3.3, too.
Also, I barely know Lisp, but this is a nifty little snippet for glomming up the jar files in the lib directory:
Of course, I prefer Ruby's Dir.glob, but, still, nifty stuff!