Change effective on 18 October 2012
Heroku now supports JDK 7 and 8 (with lambdas) in Scala and Play 2 applications. To take advantage of the new support, specify a version in
system.properties and push your app to Heroku to get a newer JDK. If you’ve never created a Scala app, see Getting Started with Scala on Heroku. Otherwise, take a look at our updated Scala support.