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.
Apache Click is a modern JEE Web application framework, providing a natural rich client style programming model. Apache Click is designed to be very easy to learn and use, with developers getting up and running within a day. It also supports automatic component rendering, client/server side validation, full localization, and multiple template engines (currently Velocity, JSP, and FreeMarker).
Groowiki is a Wiki program and a document management system together. It is a wiki program that utilizes Subversion, Groovy, Velocity, and many more existing products. It lets you edit Wiki pages in a tree structure just like any other wiki, but it also gives you SVN access that makes it very easy to add files to the content. It stores everything in SVN. This way all information is versioned and (optionally) accessible offline, and you can upload your modifications in batches. This is especially useful if you work with large files and the Wiki pages mainly summarize the contents of the documents.
Scripturian is a compact library that makes it very easy to integrate JVM languages (which support JSR-223). It lets you embed "scriptlets" into text documents, in the style of PHP, JSP, and ASP. It also allows boot strap JVM applications using any of the supported languages, which makes it easy to quickly configure and make changes in how your applications start up without re-compilation.
jmxtrans is effectively the missing connector between JMX and whatever logging or graphing package that you can dream up. jmxtrans is very powerful tool that reads JSON configuration files specifying servers/ports and JMX domains/attributes and then outputs the data in whatever format you want via special "Writer" objects that you can code up yourself. It does this with a very efficient engine design that will scale to querying literally thousands of machines. The core engine is pretty solid and writers are included for cacti/rrdtool, graphite, and stdout.
Journal is software for developing and publishing journals on the Web. It combines Java, Spring 3, Lucene, and Ehcache into an elegant solution for Web content management. The presentation is modern and CSS-based, and uses a responsive approach to layout. Resize your browser window and watch the layout adapt.