In order to dump location information in the stacktrace, the getMessage() method of a Locatable exception should return a concatenation of the raw message (given in the constructor) and the exception's location, e.g.
getMessage()
Exception
RuntimeException
The first location of the collection returned by MultiLocatable.getLocations() should be be identical to the result of org.apache.cocoon.util.location.Locatable.getLocation .
If the list of locations designates a call stack, then its first element should be the deepmost location of this stack.