ExceptionHandler

A HttpHandler that delegates to an underlying handler.  In the case of an exception during execution of the underlying HttpHandler dispatch to a different HttpHandler based on the Exception's class.

The order the exception handlers are added is important to handle inheritance.  I noticed some of the JAX-RS exception mappers try to calculate the inheritance depth to handle this.  I don't think it needs to try and be that clever.
If there is no match the exception should not be discarded, we should probably have some kind of fallback handler for any exception type that is not explicitly listed.