Google Web Toolkit – Build AJAX apps in the Java language
Download Google Web Toolkit (GWT)
Google Web Toolkit (GWT) is a Java software development framework that
makes writing AJAX applications like Google Maps and Gmail easy for
developers who don’t speak browser quirks as a second language. Writing
dynamic web applications today is a tedious and error-prone process; you
spend 90% of your time working around subtle incompatabilities between web
browsers and platforms, and JavaScript’s lack of modularity makes sharing,
testing, and reusing AJAX components difficult and fragile.
GWT lets you avoid many of these headaches while offering your users the
same dynamic, standards-compliant experience. You write your front end in
the Java programming language, and the GWT compiler converts your Java
classes to browser-compliant JavaScript and HTML.
http://code.google.com/webtoolkit/