JRuby

From https://www.jruby.org/news

# have javac
docker run -it --rm -v $(pwd):/app -w /app jruby:10.0.2.0-jdk bash

# no javac
docker run -it --rm -v $(pwd):/app -w /app jruby:10.0.2.0 bash
docker run -it --rm -v $(pwd):/app -w /app jruby:9.4.9.0 bash

# packages you want
apt-get update
apt-get install -y git gcc

javac is needed to build Puma, for example (issue)