You have 4 options right now on GCP:
GCE - runs VMs same as ec2
GKE - runs docker containers instead of full VMs
Managed VMs - these are appengine apps running in a less sandboxes environment, basically containers with access to managed services using 'native' APIs (as opposed to service calls)
GAE - appengine, a PaaS in a fully managed environment, you deploy code and they run on their own, accessing services as native APIs
You can run a servlet 3.x app in the first three, with different levels of operational effort.
Right now, GAE is servlet 2.5 (Java 7). Don't hold your breath for this to change, it's been on the roadmap for years (although we're all very hopefully)
Managed VMs are not GA yet either, which may affect your choice.
Regarding play, I can't help there.