This greatly reduces the work that you need to do. However, the look will not carry forward to other platforms. For that, you need to paint your own buttons as I mentioned in my earlier blog.
The technique for rendering leopard like toolbar button is :
- Create a transparent PNG icon for the button - for example, a plus sign
- Create a JButton and set button.putClientProperty("JButton.buttonType", "segmentedTextured") and various other options in apple's technical note website.