FreeSB is a (service oriented) alternative to hub-and-spoke messaging, enabling new and legacy systems to plug in to the bus and communicate with other systems on it, thus providing loosely-coupled application integration. FreeSB is currently implemented in Java but ESB clients should be implementable in other languages (Python, .Net, etc.).
Roundhouse is a modular J2EE application platform that allows applications to combine Struts modules, JSR-168 portlets, and Web services into a single application. It is intended to take the drudgery out of new J2EE application development by providing existing user and security architecture, navigation, and logging although it can be used standalone with no additional development. It ships with forum and blog modules along with several handy portlets which essentially make it a a portal based blog and forums application. The architecture is Struts-based and includes a Struts-based JSR-168 Portlet container. Developers extend Roundhouse by creating new standalone modules which can be independently developed without mucking around in the Roundhouse codebase and merged with Roundhouse and any number of other modules at build time. Modules can be created, packaged as MARF files, and redistributed.
Apache Rivet is a system for creating dynamic Web content via a programming language integrated with Apache Web Server. It is designed to be fast, powerful and extensible, consume few system resources, be easy to learn, and to provide the user with a platform that can also be used for other programming tasks outside the web (GUIs, system administration tasks, text processing, database manipulation, XML, etc.). It is similar to PHP, except that it uses Tcl, and provides both HTML/Tcl pages as well as pure Tcl pages to aid the programmer in separating logic and presentation when necessary.
Rome is a set of Atom/RSS Java utilities that make it easy to work in Java with most syndication formats. It accepts all current flavors of RSS (0.90, 0.91, 0.92, 0.93, 0.94, 1.0, and 2.0) and Atom 0.3 feeds. Rome includes a set of parsers and generators for the various flavors of feeds, as well as converters to convert from one format to another. The parsers can give you back Java objects that are either specific for the format you want to work with, or a generic normalized SyndFeed object that lets you work on with the data without bothering about the underlying format.
WidgetServer is a Java/XML server-side GUI-framework which enables an application to run as either a monolithic Swing app, a client/server Swing app, or as a Web app without any change and without loss of functionality. An Eclipse Plugin is available as well. A rich widget set is supported that includes tree views, tabbed panes, split panels, and much more. Animations, all types of events, and several effects are supported, as well. A unified widget-based, object-oriented programming interface for Web and Swing GUIs is offered to the developer to control and assemble the GUI. Web applications are fully AJAX enabled. For Swing client/server applications, the framework handles client/server communication, including compression and security layers.