I worked with several colleagues to evaluate some of the existing Java based CMS packages (lenya, openCMS and Daisy) and daisy won (with Lenya a close second) on easy of use from both a developer and user perspective.
The primary developers are committed to the project and post often on the community boards.
Very quick wiki is incredibly quick to deploy (if you have a JSP engine). It doesn't require a database, but can be integrated with either mySQL or Oracle.
Negatives:
- Editor isn't a good as doku wiki.
- Development not a regular as one would like.
So in summary, easy to use and a great place to start if you are looking for an easy java based wiki to deploy
this is a good choice...