Not a CS, but a damn good technical accountant and well self-taught developer.
I led a team that wrote an accounting & reporting software for a specific technical problem. We had an architect who only knew Spring, and hasn't been out there pretty much in a decade.
I clashed severely with him, to the point where he made an arrogant argument about something he was clearly wrong with. He said "I bet my salary that you're wrong" in front of people. I bet mine too, and the following day I demonstrated that he was wrong. I gave him my bank account (it was pay day).
It was a hard bet to lose, so I said he didn't need to pay it, and I asked him to be removed from the team (because he showed that he wouldn't learn).
We went on to build the system without Spring, without TomCat and with more freedom to write SAL where an ORM couldn't solve the problem better.
Interestingly, we used grpc between the front-end and the backend JVM microservices.
As other people say, check out projects in GitHub. Look at what new Java, Kotlin, Scala projects look like.
There's a lot of interesting stuff in JVM-land that don't touch Spring.
Interestingly on the software that we wrote, compute was the biggest bottleneck. I rewrote some parts in Rust, but ended up canning the work because nobody else would be able or willing to touch the code.
Yes, Spring Boot is very popular, but there is a whole world of Java outside Spring, even if you confine yourself to just web apps (which is far from the only domain in which Java is used).
