Red Hat Enterprise Applications is an open-source suite of products that includes content management, portal, and web development software, all based on the J2EE standard.

OpenCms is a professional level Open Source Website Content Management System. OpenCms helps to create and manage complex websites easily without knowledge of html. An integrated WYSIWYG editor with a user interface similar to well known office applications helps the user creating the contents, while a sophisticated template engine enforces a site-wide corporate layout.

Joomla! is one of the most powerful Open Source Content Management Systems on the planet. It is used all over the world for everything from simple websites to complex corporate applications. Joomla! is easy to install, simple to manage, and reliable.

Nukes on JBoss is a full fledged Content Management System (CMS) with advanced user/group management, security rules and pluggable components. Components can be deployed at runtime while the application is running. It is all written in JBoss ...

Webman is a professional content management or website production system. It was used in more than forty big websites in germany. (look at the history section) Webman is completly written in java and supports three relational databases: Oracle, Sybase and PostGreSQL. Have a look at the product info page for more information.