Google Java Module is a open source java based library to provides an elegant and feature rich Google Charts visualizations within a GWT application and can be used along with GWT widget libraries. There are chapters discussing all the basic components of Google Charts with suitable examples within a GWT application.
Google Web Toolkit (GWT) is a development toolkit for building and optimizing complex browser-based applications. GWT is used by many products at Google, including Google AdWords and Orkut. GWT is an open source, completely free, and used by thousands of developers around the world. It is licensed under the Apache License version 2.0.