we have a project written in Java. It is a maven project, that has jsp pages and a lot of java code:
This: http://scala-tools.org/mvnsites/maven-scala-plugin looks like a good way to integrate your Scala code into your Maven build, though I haven't tried it. (I use SBT, which does Scala/Java integration nicely, as well as IDE project creation (Idea & Eclipse) via plugins. You wouldn't want to change your whole build process, though).