An App Engine guestbook using Java, Maven, and the Cloud Datastore API via google-cloud-java.
Please ask questions on StackOverflow.
First, pick a project ID. You can create a project in the [Cloud Console] if you'd like, though this isn't necessary unless you'd like to deploy the sample.
Second, modify Persistence.java: replace your-project-id-here with the project ID you picked.
Then start the Cloud Datastore Emulator:
gcloud beta emulators datastore start --project=YOUR_PROJECT_ID_HERE
Finally, in a new shell, set the Datastore Emulator environmental variables and run
mvn clean appengine:run
mvn clean appengine:deploy