dotCMS
dotCMS is a JSR-168 compliant portal based open source content management system written in Java. It supports all the standard CMS features such as content staging, content versioning and content workflow.
dotCMS also supports inline content editing and WYSIWYG editor. It also offers third party integration with Liferay portal and OSCache.
dotCMS comes in 3 different distributions - open source, .edu edition and associate edition. Only the open source edition is free. Most of the advanced features are missing in the open source edition.
Jahia CMS for Java
Jahia is an open source Java based content management and portal system. Jahia includes an integrated JSR-168 portal system.
Jahia supports versioning, staging, locking and workflow features. It also provides complete multi lingual support. Jahia also contains a document management system with WebDav support and Integrated search engine (Apache Lucene).
Jahia is available in different distributions - community, standard, professional and enterprise. Only the community edition is free. No support is available for community edition. Enterprise features such as single sign on, LDAP and Active directory support, Load balancing/clustering etc. are NOT available in community edition.
OpenCMS by Alkacon
OpenCMS is a content management system based on Java and XML. It can be used to manage content on a public Website without requiring any coding skills. It also has an approval workflow to ensure review of the content pushed to the public site. Check out some of the sample sites here.
Some of the key features of OpenCMS are WYSIWYG editor, Preview function, JSP integration, Structured content, image processing, search engine, unicode support, security permission system, undelete support, WebDAV support, advanced user management and context menus based on Ajax.