Code reuse is one of the biggest mantras in development projects, so what are you to do with your old Java code-base if you want to start using Scala ? This post by Daniel Spiewak's disusses the interoperability capabilities between Java and Scala. Read Daniel Spiewak's post 'Interop Between Java and Scala': http://www.codecommit.com/blog/java/interop-between-java-and-scala