Griffon is an application framework for developing desktop applications in the JVM, with Groovy being the primary language of choice.
Inspired by Grails, Griffon follows the Convention over Configuration paradigm, paired with an intuitive MVC architecture and a command line interface.
Griffon also follows the spirit of the Swing Application Framework (JSR 296), it defines a simple yet powerful application life cycle and event publishing mechanism.
Grails developers should feel right at home when trying out Griffon.
Many of Grails' conventions and commands are shared with Griffon.
Granted, Swing is not the same as HTML/GSP but Builders simplify the task of creating the UI.