I've been using Rails for 15 years, and probably written or supported 20 apps with it. In all the reading I've done on it, and all the work I've done with it, I've never used JRuby, nor seen it implied that this was the "correct" way to run an app in production. As an appeal to authority, Heroku's default is MRI.

> Funny, since for a long while, the "correct" way to run Ruby workloads in production was to run JRuby, therefore Java.

cite please?

I've worked with Rails since 2008 (as well as a lot of other languages) and JRuby has rarely been used.

jruby was definitely the play in 2008-2012, reason being that puma wasn't out yet and everything else was doggedly slow, so you used to use tomcat or glassfish.

Since jruby is being interpreted into java (thus, bytecode), the resulting performance (throughput and latency) was a lot better and the lack of jemalloc (a good allocator by most means!) meant that your memory growth was a little more sawtooth and a little less... growy.

I think these days most folks are just running something like puma.

Not really.

1. Java != JVM

2. If JRuby is basically just Java, then keep going. Everything becomes binary at some point, therefore Python/JS/Ruby/etc are just binary.

Worked on a big project like that once. The day we put JRuby out to pasture was a great day indeed.

In all of the Ruby projects I've been involved with, the only one that ran JRuby is a startup that failed.