[nitwit005]

The Java frameworks are "modern". They're common to use in new projects, and the Javascript frameworks often mimic them.

That said, I'd honestly start by ignoring the common frameworks and just use something like Jetty embedded to create some API endpoints.

There's a lot of learning required for the common frameworks like Spring Boot. Browse the documentation and you'll see there's a lot there. Plus, they tend to be a debugging challenge for new people due to use of reflection and the like.