Google Web Toolkit Features（cited from its website)
- To communicate from your web application to your web server, you just need to define serializable Java classes for your request and response. In production, GWT automatically serializes the request and deserializes the response from the server. GWT's RPC mechanism can even handle polymorphic class hierarchies, and you can throw exceptions across the wire.
- No, AJAX applications don't need to break the browser's back button. GWT lets you make your site more usable by easily adding state to the browser's back button history.
- Your GWT applications automatically support IE, Firefox, Mozilla, Safari, and Opera with no browser detection or special-casing within your code in most cases.
- GWT's direct integration with JUnit lets you unit test both in a debugger and in a browser...and you can even unit test asynchronous RPCs.
- Easily create efficient internationalized applications and libraries.
- All of the code for GWT is available under the Apache 2.0 license. If you are interested in contributing, please visit Making GWT Better.