The Google Web Toolkit

Google Web Toolkit (GWT)

is an open source Java software development framework that makes writing AJAX applications easy. With GWT, you can develop and debug AJAX applications in the Java language using the Java development tools of your choice. When you deploy your application to production, the GWT compiler translates your Java application to browser-compliant JavaScript and HTML.

• Check out this sample application

Then get really clever with third party tools

• Instantiations GWT Designer - GWT Designer is an Eclipse plug in that lets you use WYSIWYG tools to build web applications visually. You can add controls using drag-and-drop, add event handlers to controls, and edit properties in a properties tab.
• GWT Widget Library - Robert Hanson's GWT Widget Library includes open-sourced widgets you can use in developing your GWT application. The library includes easy support for pagination and calendars.
• More...