JRuby is an implementation of the Ruby language using the JVM. It aims to be a complete, correct and fast implementation of Ruby, at the same time as providing powerful new features such as concurrency without a global-interpreter-lock, true parallelism, and tight integration to the Java language to allow you to use Java classes in your Ruby program and to allow JRuby to be embedded into a Java application.
You can use JRuby simply as a faster version of Ruby, you can use it to run Ruby on the JVM and access powerful JVM libraries such as highly tuned concurrency primitives, you can use it to embed Ruby as a scripting language in your Java program or many other possibilities.
- Substantial memory reduction (~24% less heap with a simple Rails app)
- Reduced runtime generation of specialized objects and variable scopes
- Enumerator#next logic replaced with Fiber
- Better handling of argument lists passing through Enumerator
- Open Java modules bind methods correctly
- IO and process control improvements on Java 9+ and on Windows
- More robust handling of optimized call paths for Fixnum, Float
- 90 issues fixed for 184.108.40.206