How to run the App Engine Project in Eclipse:
The App Engine SDK includes a web server for testing your application in a simulated environment. The Google Plugin for Eclipse adds new items to the Run menu for starting this server.
To run your application in the web server inside the Eclipse debugger, select the Run menu, Debug As > Web Application. Eclipse builds the project, switches to the Debug perspective, and the server starts. If the server starts successfully, the server displays several messages, including a message similar to the following, in the Console:
The server is running at http://localhost:8888/
With Eclipse, you can leave the server running in the debugger while you make changes to source code, JSPs, static files and appengine-web.xml. When you save changes to source code, Eclipse compiles the class automatically, then attempts to insert it into the running web server dynamically. In most cases, you can simply reload the page in your browser to test the new version of the code. Changes to JSPs, static files and appengine-web.xml are recognized by the development server automatically, and also take effect without restarting the server. If you change web.xml or other configuration files, you must stop and start the server for the changes to take effect.
To stop the server, make sure the Debug panel is selected, then click the Terminate button: