Need to be able to control how ClassNotFound are generated

In Ceylon, when we use JBoss Modules for Maven interop, very often we have ClassNotFoundException when a Maven module does not declare its dependencies correctly. Often the missing class will actually be in a transitive dependency.

I'd like to be able to override a method that lets me generate a more helpful exception message, which would include advice on where to find the missing class and how to fix it using a config file. But for that I need to be able to override some method on Module where we throw the exception to provide an alternative error message, and (unless already available) a way to traverse other modules to find where the missing class is.