JRuby is a really cool project! Unfortunately it's fairly far behind mainstream Ruby. They are still working on Ruby 2.7 compatibility, but Ruby 2.6 end-of-life

JRuby is a really cool project! Unfortunately it's fairly far behind mainstream Ruby. They are still working on Ruby 2.7 compatibility, but Ruby 2.6 end-of-life is 2022/03/31 (tomorrow).