Open Source Content Management Systems (CMS) in Java

Walrus CMS is easy to use intuitive edit-in-place java based content management system. What makes Walrus stand out is that it does not have separate administration interface - you edit your content just by point and click and drag and drop. It is built on Spring framework, employs lightweight and clean architecture, thus is easily extendible. Walrus supports several websites on one installation is easily skinnable, has undo/redo functionality. Walrus was started in 2008, so it's quite mature system working in corporate, government and non profit environments.