Introduction to the Google Web Toolkit

http://www.oracle.com/technology/pub/articles/dubois-gwt.html

Introduction to the Google Web Toolkit

by Stéphanie Antoine, Julien Dubois, and Jean-Philippe Retaillé

Learn how to use the Google Web Toolkit to do everything from basic tasks to advanced ones such as RPC communication, history management, and packaging a production-ready application.

http://code.google.com/webtoolkit/documentation/com.google.gwt.doc.DeveloperGuide.Fundamentals.html

Fundamentals

Core GWT concepts such as
* compiling Java source into JavaScript
* debugging
* cross-browser support, and
* defining modules.