Automattic Kismet (Akismet for short) is a collaborative effort to make comment and trackback spam a non-issue and restore innocence to blogging, so you never have to worry about spam again. Akismet Java is an API for interacting with Akismet.
blojsom is a full-featured, multi-user, multi-blog package written in Java. blojsom aims to retain simplicity in design while adding user flexibility in areas like back-end storage, flavors, templating, themes, and plugins.
SimpyTools is a collection of various software for using, enhancing the http://simpy.com/ social bookmarking service. The software includes libraries in various programming languages, for using the REST API of simpy.com, but also a FF extension and more.