It's not some great mystery: Very few people are doing low-latency in Java in the first place, and all of the people who are have probably been doing it for a l

It's not some great mystery: Very few people are doing low-latency in Java in the first place, and all of the people who are have probably been doing it for a long time (in Java) already so there's a non-trivial cost to switching from Java to $OTHER_LANG. It has nothing to do with how easy it is to achieve the performance if you really want to. Well, OK, I might grant that there are a couple of very minor things that kind of work against you in e.g. Scala, namely lack of a native 'for-which-is-a-thinly-veiled-while-loop' and such, but that can be worked around with e.g. spire's cfor or just using while loops. Compared to the amount of effort to get anything-on-JVM working well in a low-latency environment in the first place, these obstacles are all trivial.