Class file X is missing in scala

class file needed by X is missing. reference value Y of Z refers to nonexisting symbol.

This can be caused if you are using the maven-bundle-plugin to generate OSGI bundles if you forget to include the packet in the "Export-Package" list. This can be a very frustrating error to diagnose. In my option it is a bug in the bundle plugin because it allows you to export classes that are unusable. Hopefully google picks this up and saves someone in the future some time (probably me).