For the Java bit at least, this aligns with job descriptions I’ve seen and recruiter outreach I’ve received (long time ago though, maybe 5 years).

NeXT added a Java variant to WebObjects and it was for several years the main server side infrastructure, after being acquired by Apple.

Nowadays you can usually still find Java and JVM languages like Clojure (Apple Maps), on Apple's job ads.

How much of it is still Java based, no idea.

I imagine XCode Cloud has nothing to with it for example.

They moved their password monitoring service from Java to Swift.

https://news.ycombinator.com/item?id=44172166

https://www.swift.org/blog/swift-at-apple-migrating-the-pass...

Unfortunately I am the source in this case. It is from having worked on them personally. :)