swingLabs is a discontinued[1] open-source project developed by Sun Microsystems proposing extensions to the Java Swing GUI toolkit.
Available components included: The aim of the project was to experiment new or enhanced GUI functionalities that are required by Rich client applications.
It acted as a testbed for ideas related to client side technologies.
Some successful project components were eventually incorporated into the core Swing toolkit for future Java versions, although API compatibility was not guaranteed.
[1] Several repositories containing snapshots of the final development version of SwingLabs (1.6.6-SNAPSHOT) do exist, however: