Trying to get started with Google App Engine - does it work with Java 8?
I\'ve followed the instructions on this page: https://console.developers.google.com/start/ap
It's not quite the same thing, but you can use Java 8 with the new App Engine "flexible environment". I don't think you can access App Engine APIs (such as the images service or task queues) but you'll be able to use services which live outside of App Engine, such as the Datastore and Pub/Sub.
It's also worth bearing in mind that the service is currently in beta (so not covered by any SLAs). Also, the pricing is different; instead of using the normal App Engine pricing structure, it's based on usage of GCE virtual machines.