XWiki is a WikiWiki clone written in Java that supports many popular features of other Wikis like the Wiki syntax, version control, attachments, security, and searching, but also many advanced features like templates, database and dynamic development using scripting languages (Velocity, Groovy, Ruby, Python, PHP, and more), an extension system and skinability, J2EE scalability, an XML/RPC remote API, statistics, RSS feeds, PDF exporting, WYSIWYG editing, an Office viewer and importer, and a lot more.
With LinkChecker, you can check HTML documents and Web sites for broken links. It features recursion, robots.txt exclusion protocol support, HTTP proxy support, i18n support, multithreading, regular expression filtering rules for links, and user/password checking for authorized pages. Output can be colored or normal text, HTML, SQL, CSV, or a sitemap graph in DOT, GML, or XML format. Supported link types are HTTP/1.1 and 1.0, HTTPS, FTP, mailto:, news:, nntp:, Telnet, and local files.
Piggydb is a flexible and scalable knowledge building platform that supports a heuristic or bottom-up approach to discover new concepts or ideas based on your input. You can begin with using it as a flexible outliner, diary or notebook, and as your database grows, Piggydb helps you to shape or elaborate your own knowledge. Piggydb is a Web application provided as a self-contained package that contains a Web server and database engine.