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
jRuby is a Ruby implementation on the Java Virtual Machine, allowing for seamless integration with Java, while JavaScript is a highly versatile language primarily used for web development. Both languages have unique strengths and weaknesses, making them suitable for different scenarios.