Roller

Roller is a Java web application that should be able to run on any Java EE server and any relational database. Currently, Roller is best supported on Tomcat and MySQL -- but users have reported success running Roller on Glassfish, Websphere, JBoss, Resin, Geronimo, Derby, PostgresSQL, Oracle, etc.)

Here are some of Roller's key features:

• Multi-user blogging: can support tens of thousands of users and blogs
• Group blogging with three permisson levels (editor, author and limited)
• Support for comment moderation and comment spam prevention measures
• Bloggers have complete control over blog layout/style via templates
• Built-in search engine indexes weblog entry content
• Pluggable cache and rendering system
• Support for blog clients that support MetaWeblog API
• All blogs have entry and comment feeds in both RSS 2.0 and Atom 1.0 formats