I don't see why you wouldn't be able to use REST even if it's just one endpoint. REST doesn't say anything about the size of the API. It's just a set of design rules.
Anyway, it really doesn't matter. Do what you're comfortable with. I would use JAX-RS with Tomcat
, because that's what I like and can set up quickly. If you like Spring, use that. You wouldn't even need Java, you could even use PHP if that's what makes you happy.
As long as you use proper application design, how much requests your service can handle is mostly just a matter of hardware and configuration, not which framework you're using.