JRuby is a version of Ruby that runs on the JVM. JRuby has long been praised by Rubyists for its speed and abilities, but its compatibility with the standard (“MRI”) version of Ruby has been somewhat lacking. This talk, by JRuby developers Charles Nutter and Thomas Enebo, describes some of the major updates and improvements in the latest version of JRuby, which may convince even more Rubyists to switch.