Where I work some teams are using Java, and some are just starting to use Rust. Different problem spaces entirely though, as you said. I've seen Java used here for ETL work, Modeling & Sim work, web apps, and Android. I've seen Rust on two projects, both were real-time or near-real-time efforts.
The competition I am starting to see is between C++ and Rust, with the few teams looking at Rust loving it. I did recently help write a RFP response that noted software will be written in C++ and Rust, and the RFP was awarded to us.
I am in a different world though, as I am a contractor for the DOD. It's more like a lot of small to medium sized companies than one big company, which is why some groups can use Java and others C++ and others Rust.
I have the same problem of differentiating between hobbyists and professional experience, both on HN and when interviewing. I had someone tell me they knew Java, then found out they had done maybe 5 months of Java work and didn't know some of the most basic things.
As for myself, in terms of writing professional software for clients, I've done
the following, in order of amounts worked: Java, C++, Python, Javascript, Erlang, R, Ruby, Clojure, C, Scala, and C#. I've done Rust and Elixir in personal projects, but not yet for clients. I plan to transition to a full-time Rust project in the coming years.
