Well, I've used http://www.junitdoclet.org/
(why doesn't the URL tag work???) once, but stopped using it because I found that my unit tests selfdom have a one to one match with how a class looks like. Sometimes they do, but mostly they don't. I also dislike all the comments JUnitDoclet puts in my code, but that's personal taste.
There seems to be an upcoming release 2.0 for JUnitDoclet, but I haven't checked the activity in CVS if this is soon to be arrived.
---- Trond trond dot andersen at gmail dot com