Google Web Toolkit - Build AJAX apps in the Java language

Google Web Toolkit (GWT) is a Java software development framework that makes writing AJAX applications, like Google Maps and Gmail, easy for developers who aren’t fluent in the intricacies of browser quirks. Writing dynamic web applications today is a tedious and error-prone process; you spend 90% of your time working around subtle incompatibilities between web browsers and platforms, and JavaScript's lack of modularity makes sharing, testing, and reusing AJAX components difficult and fragile.