Somehow, Java became screaming fast and/or Lucene manages to avoid all the parts of Java that are screaming slow. Therefore Elasticsearch. Therefore that's one very good reason that Java won't go anywhere right away.
Also, despite the existence of obviously saner alternatives like REST, many enterprises use Java as a standard for service bindings. Long ago lost to the sands of time is the original intent that XML was intended to be human-readable (in the sense of not needing binary decoding) but not human-written.
I wrote a lot of semi-interesting Java in the past, and I suppose there was a time when I liked it, but I can't see that time coming again. Java is annoying. It's that grumpy, square, didactic, great uncle whose clothes haven't been updated since the 70s and whose house smells musty and who tells you about how he took no shortcuts in his life and you can't either.
Python is annoyingly gimpy (what sort of interpreted language deliberately doesn't have closures and first class functions?) but at least you can write a command-line tool in it, and maybe some day it'll be fast too. I guess dumbed down is better than a smelly old uncle.
Maybe I'll get to write some Rust soon.