Moving from CRuby to JRuby dropped one app from 20 extra large EC2 instances to 10 medium ones. Tens of thousands of dollars saved with a better runtime. #JRuby #EC2 #CloudCosts

JRuby is fully parallel on the JVM, which exposes thread-unsafe Ruby code. The fix was years of educating the Ruby community about thread-safe programming. #JRuby #Concurrency #Ruby

A $50 ticket, 60 people, and a Java dev who understood every Ruby slide. That's how Charles Nutter walked into RubyConf 2004 and ended up building JRuby. #JRuby #Ruby #Java