Joker is a straightforward sample of a joke telling app with multiple flavors that uses multiple libraries and Google Cloud Endpoints. It consist of four modules: A Java library that provides jokes, a Google Cloud Endpoints (GCE) project that serves those jokes, an Android Library containing an activity for displaying jokes, and an Android app that fetches jokes from the GCE module and passes them to the Android Library for display.
To get started install the Google Cloud SDK and follow the setup instructions: https://cloud.google.com/endpoints/docs/frameworks/java/migrating-android
Then clone the repository and get the code running on Android Studio.