XWiki

"XWiki is a WikiWiki clone written in Java which supports many popular features of other Wikis like:

* Wiki syntax (uses Radeox engine)
* Content management (view/edit/preview/save)
* Version Control
* Attachments
* Rights Management
* Full-text Search

XWiki also has many advanced features that many other wiki engines lack:

* Document Templates to ease creation of common documents.
* Relational Database storage using Hibernate.
* Design Engine for Meta-Data and Forms.
* In-place (inline) editing of form information in pages.
* Powerful programming API in documents (Velocity or Groovy)
* Search API for more detailed searching in the Meta-Data.
* Plugin System in Java.
* Scalability and Performance using J2EE.
* Complete Design Skin System (templates content as well as CSS) have a look to nice websites powered by XWiki
* RSS output and display of external RSS feeds
* Multi-Lingual capabilities
* XML/RPC Remote API
* Portlet Integration
* Integrated Statistics
* PDF Export
* WYSIWYG HTML Editing"

XWiki Features:

XWiki Features Page

XWiki User Screenshot: