Have a look at GWT Google APIs.
http://code.google.com/p/gwt-google-apis
The Google API Libraries for Google Web Toolkit is a collection of
libraries that provide Java language bindings for popular JavaScript
APIs such as the Google AJAX Search API, Gears API, Maps API,
Visualization API, and Gadgets. These libraries make it quick and easy
for you to use these JavaScript APIs in your Google Web Toolkit
project without having to write custom integration code using
JavaScript.