The Play framework is the most fun I’ve had developing Java web applications. It’s fast, natural, comes with a rails-like scaffolding for CRUD operations on your model, has built-in Selenium testing as well as unit and functional tests, and most importantly Just Works.

It also deploys natively onto Google App Engine, but this isn’t described very well in the official documentation so here are the basics:

Get started

1. Get yourself a GAE account and set up an application. you will need the ID.
2. Download a recent nightly of the stable 1.0 branch (1.0 final doesn’t work with GAE, and Play needs to sort out its versioning system here)
3. Unzip
4. Download the GAE SDK for Java
5. Unzip
6. Create your app (although use Siena rather than JPA if you want to persist to the GAE data store) and configure it to use the GAE module
7. Add your GAE application ID to myapp/war/WEB-INF/appengine-web.xml

Deploy to a local dev GAE environment

1. run play war myappname -o myappname-war
2. run APPENGINE_SDK_DIR/bin/dev_appserver myappname-war

Deploy to the GAE server

1. run play war myappname -o ../myappname-war
2. run APPENGINE_SDK_DIR/bin/appcfg update myappname-war/
3. log in to your app engine console and check out your application!