Mac Widgets for Java is a collection of widgets seen in OS X applications, offered in a Java API. These widgets help Java developers create more Mac-like applications. Their usage is not restricted to Mac though, as they will render across platforms.
Guiding Design Principle
Mac Widgets for Java have been designed as components - so you won't see much inheritance. Component style designs help make the API simple and understandable. This stye of design also makes it easy for developers to use the components as they were intended to be used.