Absolutely ridiculous comment. You added nothing to the discussion and gave no justification for a frankly ignorant standpoint. I can speak for two of them: JRuby is an absolute godsend even if you aren't massively interested in Ruby - Java libraries/classes + a REPL is a phenomenally powerful combination and makes learning new libraries incredibly easy. Groovy I am not a fan of for significant development, but it's great for DSLs, and in particular gradle is the nicest way I've found to manage dependencies and project setup.