Getting Rid of Package-Based GWT URL's
Deploying a fancy GWT application loses a lot of its shine when you see a my.package.gwt url in your browser. To get rid of this, you only need two extra lines of configuration in your application module:
This source node points to the Java application implementation, the public node to the application's resources.
There's one thing you need to keep in mind, though: both paths are considered to be relative to the module configuration file.