Google today launched Google Web Toolkit (GWT) that is a Java software development framework that makes writing AJAX applications like Google Maps and Gmail easy for developers.
Google Web Toolkit Getting Started Guide can teach you how to install the Java SDK, download and install the Google Web Toolkit SDK, and build a Sample Application.
GWT is a cool way of helping developers leverage that expertise in their own AJAX apps. And did I mention it is free, for both commercial and non-commercial use, and available for all countries. Download the Google Web Toolkit (GWT) SDK that has everything you need to write web applications using GWT, including the GWT compiler, hosted web browser, class libraries, and a number of sample projects to get you started.