The Quaqua Look and Feel (Quaqua) is a user interface library for Java applications which wish to closely adhere to the Apple Human Interface Guidelines for Mac OS X.

Sun's Metalworks Demo running with the Quaqua Look and Feel
Quaqua is not a fully self-contained look and feel. It runs on top of Apple's Aqua Look and Feel, and provides fixes and enhancements for it.
Features
- (Nearly) Native User Experience
Quaqua user interface delegates closely look and behave like their native counterparts. Complex user interface components, such as JFileChooser and JColorChooser, are close enough to make end users feel comfortable with them. - Blends into OS X Designs
Quaqua supports three OS X designs: Tiger, Panther, Jaguar. Quaqua automatically chooses the right design for the current operating system. - Alternative Styles
Quaqua offers alternative styles for many user interface elements. Such as small styles for most of the components, as well as a striped style for tables, lists and trees. Jaguar-design like tabbed panes with stacking tabs are also supported. - Additional Components
Quaqua provides Swing implementations of NSBrowser and NSSheet (named JBrowser and JSheet). - Clean Layout
Laying out Aqua components with Java is quite challenging. Quaqua provides an API for component alignment based on visual criteria (baseline, visual bounds, preferred gaps). JScrollPane's automatically avoid overlaps with the grow-boxes of windows.
- Localized in four languages
Quaqua is localized in the following languages: German, French, Italian and English.
License Fee
Quaqua is free for commercial and non-commercial use.
If you want to honour my work on this project,
send me a bottle of good wine.
Editions
The Quaqua Look and Feel is available in two editions.
- A full fledged edition providing as much user interface elements by Quaqua as possible.
- A smaller file chooser only edition, which only provides user interface for JFileChooser's - all other user interface elements are taken from the Aqua Look and Feel which ships with Apple's Macintosh Runtime for Java.
Supported Platforms
The Quaqua Look and Feel supports Apple's J2SE 1.4, J2SE 5 and J2SE 6 and SoyLatte J2SE 6 on Mac OS X 10.4 and 10.5.
Altough Quaqua works J2SE 6, it provides limited support for features which go beyond J2SE 5.
The Quaqua native libraries support PowerPC and Intel Macs with 32-bits or 64-bit processors. Quaqua will work without these native libraries, but user experience degrades.
Due to copyright restrictions and technical constraints, Quaqua can be run on non-Mac OS X systems for development purposes only.