Qt is a comprehensive, object-oriented development framework that enables development of high-performance, cross-platform rich-client and server-side applications. When you implement a program with Qt, you can run it on the X Window System (Unix/X11), Apple Mac OS X, and Microsoft Windows NT/9x/2000/XP by simply compiling the source code for the platform you want. Qt is the basis for the KDE desktop environment, and is also used in numerous commercial applications such as Google Earth, Skype for Linux, and Adobe Photoshop Elements.
XWidglets is a complete rich Java Swing tool for designing, creating, and using XML-based GUIs. It provides a lightweight XML client, clear separation between view, data, and process, MVC I and II support, event management, a consistent look and feel across platforms, a rich set of GUI components, and n-tier architecture integration.
Java Tiny Gfx Library (JTGL) is a graphic foundation framework (a graphics/gaming API) that will allow easy deployment/porting of applications/games on many environments: AWT, Swing, J2ME (MIDP 1&2, Nokia, and Siemens), SuperWaba (PalmOS, PPC, and Symbian), ExEn, DoJa, and others.
The DisGUISE C# library provides easy and object-oriented access to the advanced features of the AT command interface available in Sony Ericsson cellphones. This includes basic tasks like querying the phone book or getting a notice on incoming or outgoing calls, as well as creating and handling advanced GUI elements. The phone, connected via Bluetooth to the computer, thus can become an additional user interface element.
XUI is a Java and XML platform for building Rich Internet Applications. The platform greatly reduces the amount of code needed to build feature rich applications on a wide range of systems. The project includes plug-ins for both NetBeans and Eclipse, plus support for AWT, Swing, SWT, J#, and HTML.
The Ecere SDK is a cross-platform toolkit for building software applications. It currently runs on Windows, Linux, Mac OS X (through X11), FreeBSD, and the Android OS. It should run on other Unix platforms with minor testing/tweaking. With the Ecere SDK, you can develop applications once and deploy them on all supported platforms alongside a lightweight runtime environment. It introduces eC, an object oriented language derived from and fully compatible with C, compromising neither runtime performance nor ease of use. A built-in 3D engine supporting both Direct3D and OpenGL is fully integrated.
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.