I think the backend SDK would sit on that.
Not sure of the best way to get the core serverless, though. Most of the devs at my workplace are Java devs too, and we're migrating to a serverless architecture. Lambda etc supports Java, but the cold start times on many applications can be debilitating.
We have a Proof of Concept lined up to try https://quarkus.io/guides/amazon-lambda for some Java, to see if that helps, but we haven't got any results on that yet