DomUI is an easy to use framework to create AJAX rich web based user interfaces using only Java as the language and open sourced using the LGPL 2.1. It has a lot of predefined components, and allows you to easily define your own- without writing any Javascript! In addition it is an application framework which encapsulates many best practices, makes you DRY (Don't Repeat Yourself), and saves developers time by making simple things simple (while allowing for complex things).

Source: DomUI