If you have a web server (Apache, IIS, etc.) installed locally and PHP installed, you can write a PHP script to generate stock data and make the call to your local server. What's important for this example is that the stock data is JSON-encoded and that the server is local.
ant buildscript to create the production mode files for the application (which will now include stockPrices.php).
Move the compiled StockWatcher files in the StockWatcher/war directory to a /StockWatcher directory in whatever web server (Apache, IIS, etc.) you have installed locally which supports PHP. If you are not using Java servlets (e.g. GWT RPC), you will not have to move over the files in StockWatcher/war/WEB-INF
Test the stock quote server.
Now that you can retrieve JSON-encoded stock data from the server, continue with the next step in the JSON tutorial, Manipulating JSON data in the client-side code.