Schools use it because it used to be the best way to get a job. Not anymore.
Java is the most in-demand technology in my home country, Estonia. Java also has around 800 open positions at any given time where I live now (Buenos Aires, Argentina). In fact, pretty much everywhere I've looked, Java is consistently one of the best ways to get a job simply because it has the most jobs available.
HN favourites like Go and Rust? I haven't yet found a city in Europe that would have more than 10 job offerings for either of them.
However, the sausage is still made Java. Amazon, Google, and Apple are, as far as a I know, primarily Java shops. It's just no one ever starts a blog with "Here's something cool I did in Java".
Outside of USA, a little digging I did via Glassdoor:
Buenos Aires, Argentina: - Rust: ~5 jobs - Go: ~3 jobs - Java: ~800 jobs
Lisbon, Portugal: - Rust: ~6 jobs - Go: ~30 jobs - Java: ~278 jobs
Barcelona, Spain: - Rust: ~1 job - Go: ~50 jobs - Java: ~751 jobs
These are just places I've lived at and while I can see Go slowly becoming a thing, Rust is still half a decade away from anything tangible for the real world I would say. So if anyone asks me what should they become an expert in for the next 10 years, I would not hesitate to say Java.
Additionally, pretty much all the distributed data processing tools run on the JVM, which is a big deal if that's what you do for a living.