Why would you ever pick a language like this for HFT? It seems like a nonstarter for me but I guess Java is out there in use

There are plenty of domains where the competition is not one of pure latency (where FPGAs and custom hardware have even taken over from C++). In these domains managed languages can be sufficient to get to "fast enough" and the faster iteration speed and other comforts they provide can give an edge over native languages.

"Why we chose Java for our High-Frequency Trading application"

https://medium.com/@jadsarmo/why-we-chose-java-for-our-high-...