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.
GTK, which stands for the Gimp ToolKit, is a library for creating graphical user interfaces. It is designed to be small and efficient, but still flexible enough to allow the programmer freedom in the interfaces created. GTK provides some unique features over standard widget libraries.
The edit-on JavaBean SDK is a customizable, feature-rich JavaBean that allows developers to add WYSIWYG editing functionality to their AWT- or Swing-based applications. It features an intuitive word processor-like user interface that enables XHTML content authoring with XML markup, and has a royalty free run-time license.
Surftree is an applet that displays data organized in a spreadsheet as an expandable tree on a Web page. The tree can be 9 levels deep and have over 65,000 nodes. Each node can display up to 4 independent Web pages or JPG images. It works with Java 1.0 and 1.1+ and in any Web server environment.