NB: Does not include companies that started with a JVM language. The purpose of this gist is to list the companies that decided to move their stack (or some part of it) to the JVM.
- Twitter (Ruby -> Scala) - http://www.readwriteweb.com/hack/2011/07/twitter-java-scala.php
- Foursquare (PHP -> Scala) - http://www.scala-lang.org/node/5130
- Facebook (PHP/C++ -> PHP on JVM) - http://nerds-central.blogspot.com.au/2012/08/facebook-moving-to-jvm.html
- Tumblr (PHP -> Scala) - http://highscalability.com/blog/2012/2/13/tumblr-architecture-15-billion-page-views-a-month-and-harder.html
- Square (Ruby -> Java/JRuby) - http://www.quora.com/Square-Inc-1/What-is-the-technology-stack-behind-Square