It also features one of my favorite language features: after you install the jre on an OS -- and you can install multiple jres side-by-side -- you get robust, s

It also features one of my favorite language features: after you install the jre on an OS -- and you can install multiple jres side-by-side -- you get robust, single-file deploys from megajars. Which are just big zips. And this has been working for at least 25 years. No scribbling all over the OS, no system global packages, no shell games with bundler / virtualenv, and not much need for Docker. (I really like rails, but the deploy story is nowhere near as good as java.)