From GWT-Ext

Setting up the GWT_HOME System Variable

Download the GWT archive from the project's main page. Extract the archive to a local folder.

On a Microsoft Windows based machine, let's say your extract folder is C:\Program Files\Google Web Toolkit. Find your machine's System Properties and edit the Environment Variables. Add the GWT_HOME variable and set its value to C:\Program Files\Google Web Toolkit.

Setting up the GWT_HOME system variable on a Windows based machine.

Next, open up the Path system variable and add the GWT_HOME variable at the end with the following code:

<current value in path>;%GWT_HOME%;

You might need to restart your machine after this, but in most cases, restarting any open command prompt windows should be sufficient. GWT's applicationCreator and projectCreator commands should now be available throughout your machine.

Test this by opening up a command prompt at an empty folder and enter the following command:

applicationCreator com.mycompany.mypackage.client.SampleApp

This should create all the files you need for your first GWT application.

What the output should look like on a windows based machine.

You can immediately test your application by executing the following command in the same directory:

SampleApp-shell.cmd

The SampleApp module being executed in the GWT hosted browser.