JRuby has for years routed around the JVM, to maximize compatibility with standard Ruby. We've implemented byte[]-based String and Regexp, native POSIX support, and our own mixed-mode interpreting/jitting runtime atop JVM bytecode.

With JRuby 9000, we're taking this even further. JRuby 9000 introduces a new IR-based optimizing compiler, with inlining, specialization, and other tricks applied to both interpreted and bytecode-compiled code. We've also gone fully native for much of IO and Process management. This talk will show the state of this work and how it affects JRuby and the wider JVM world.