PhotoHunt: End-to-end Google+ Platform sample application
The instructions for getting started are available at: https://developers.google.com/+/photohunt/java
PhotoHunt Java runs on Google App Engine and demonstrates how to build a social application that uses Google+ Sign-In, personalization, app activities, over-the-air install, and interactive posts.
Java
The instructions for getting started are available at: https://developers.google.com/+/photohunt/java