This mackaz.de blog post shows you how to build an application using Maven, with both Java and Scala source files. Your project will be set up so that the Java-classes can access Scala-classes and vice versa.
The project automatically uses the latest Scala 2.8-Snapshot until it’s released (Maven will look for the latest version of the Scala language each time you build it). We will setup the project to use cross-compiling, so the java-classes can access scala-classes and the other way around.