JewelCLI provides an API to parse command line arguments. It uses Java annotations to present a very simple but powerful interface. Options are defined using an annotated Java interface definition. This allow a declarative style which can be much clearer than the procedural style used by some other Java CLI libraries.
Wicket Web Beans (WWB) is an Apache Wicket component toolkit for displaying and editing POJOs that conform to the JavaBeans specification. Web pages are automatically generated based on bean properties and certain conventions. If necessary, the layout, editability, and actions of these pages can be customized on an exception basis. In other words, the toolkit normally does what you'd expect, but when it doesn't, you can override its behavior.
IT Mill Toolkit is a server-side RIA (Rich Internet Application) library that provides a versatile set of AJAX widgets for Java programmers. Applications are programmed in Java and executed server-side. At the client-side (i.e. in the browser), enhanced GWT widgets are used for presentation.
The WSO2 Mashup Server is a platform for creating, deploying, and consuming Web services Mashups in the simplest fashion possible. It features support for consuming and deploying services using dynamic scripting languages, trivial deployment and redeployment, automatic and UI-based generation of Web services artifacts (e.g., wsdl, schema, policy), a set of gateways into a variety of information sources, including SOAP and POX/REST Web services, as well as plain old Web pages, and human-consumable results through a variety of user interfaces, including Web pages, portals, email, Instant Messenger services, Short Message Service (SMS), etc.
Google Gadgets for Linux provides a platform for running Google Gadgets under Linux, catering to the unique needs of Linux users. It's compatible with the gadgets written for Google Desktop for Windows as well as the Universal Gadgets on iGoogle. There are two main components to the application: one is a common gadget library responsible for running and presenting a gadget, and the other is a host program that allows the user to choose gadgets and run them on the desktop. Currently it has hosts written for GTK+ and Qt, with the GTK+ host offering a sidebar similiar to that of Google Desktop for Windows.