Google Web Toolkit

Google Web Toolkit (GWT) is a Java development framework that lets you escape the matrix of technologies that make writing AJAX applications so difficult and error prone. With GWT, you can develop and debug AJAX applications in the Java language using the Java development tools of your choice. When you deploy your application to production, the GWT compiler to translates your Java application to browser-compliant JavaScript and HTML.

Here's the GWT development cycle:

1. Use your favorite Java IDE to write and debug an application in the Java language, using as many (or as few) GWT libraries as you find useful.
2. Use GWT's Java-to-JavaScript compiler to distill your application into a set of JavaScript and HTML files that you can serve with any web server.
3. Confirm that your application works in each browser that you want to support, which usually takes no additional work.

通过java开发ajax ，b/s架构的软件可以像c/s架构软件那样开发。b/s架构其实就是c/s架构的一个特例，只不过使用http协议通信，客户端都运行在相同的软件上（浏览器）。b/s的优点就是瘦客户端，用户几乎不需要安装软件，就可以直接使用服务器提供的服务。随着ajax的热火，客户端增大的趋势也在上升，原来简单的模式带来了性能上的劣势，ajax的异步通信就是为了弥补这个缺陷，同时给用户提供更好的体验。但是在使用javascript,dom,css,html开发客户端，编写，调试都不方便。现在GWT的出现来解决这个问题。

GWT提供了html上的所有控件 button.text,tree,tab,frame,list等，这很像vc/bc的界面开发包，以后将可以在web上很方便的构建客户端界面。

google让ajax火了起来，google又让ajax 容易起来。