Project Looking Glass, a three-dimensional desktop and application development tool, was first released in the summer of 2003. The technology is designed primarily to enable developers to manage and manipulate desktop user interfaces, including the ability to use window transparency, rotation and zoom capabilities as well as multiple desktop workspace management and miniaturization features. Developers can, for example, create desktops where users can turn windows onto book-like "spines" or to manage multiple window layers through the use of a transparent interface.
The announcement is notable because Sun has previously licensed development tools under more restrictive terms than those allowed under the General Public License. The GNU license allows developers to copy, modify and redistribute technology, and also preserves those rights in derivative works.
Sun recently announced that it was considering licensing its Solaris operating system under an open source model. The company has drawn criticism, however, for refusing to commit to licensing Solaris under a true open source license, as opposed to taking a more ambiguous approach to open source development.