App Engine Dev Tips #1 : Beware of Multiple Local Running Versions

App Engine provides a great development environment based on Eclipse to development and test out your application locally. Once everything looks good, you simply have to deploy the application into the cloud with one click.

But often you find the following scenario crop up. Its happens more  with newbies but also with experienced devs, trust me on that one.

  1. You develop your code and launch the application locally via Run As -> Web Application.
  2. You test out your application by visiting localhost:8888 (any other port depending on your local environment)
  3. You go back to Eclipse, make some other fixes/changes and inadvertently launch the Web application again.
  4. You go to the browser, expecting your latest changes to be there. You keep refreshing but it still shows the old version.

Assuming that you have made your changes correctly, chances are the old instance of the web application is still running and it is serving the requests from the browser.

To avoid this, ensure that only one instance of your web application is running and that all the old ones are killed. 

The following is a screen shot of my development environment that has 2 instances running.


Don’t let this happen. It is better that before every launch, you have terminated all running instances. Just make that into a habit and it will save you countless hours.

Check out all the App Engine Development Tips.


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