JRuby is an implementation of the Ruby programming language atop the Java Virtual Machine, written largely in Java. It is free software released under a three-way EPL/GPL/LGPL license.
License: Open Source
Groovy is a dynamic language on the Java platform, making it a good choice for Java developers looking for a more concise syntax. On the other hand, jRuby is an implementation of Ruby that runs on the Java Virtual Machine, providing access to Java libraries while retaining Ruby's flexibility.