One of my favorite CMS application in Java is OpenCMS.
Here's some information about OpenCMS from its website:
"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. As true Open Source software, OpenCms is completely free of licensing costs."
Any thoughts about this guys?