The Google Web Toolkit (GWT) is a toolkit to develop Ajax web application with Java. The programmer writes Java code and this code is translated into HTML and Javascript via the GWT compiler.

The compiler creates browser specific HTML and JavaScript to support all the major browsers correctly. GWT supports a standard set of UI widgets, has build in support for the browser back button and a JUnit based test framework.

GWT provides two modes:

Development Mode: allows to debug the Java code of your application directly via the standard Java debugger.

Web mode: the application is translated into HTML and Javascript code and can be deployed to a webserver.