ExceptionHandler issues

ExceptionHandler.getRootCause may return null if the exception is a FacesException without a reason (this may also be a myfaces bug). This causes an IllegalArgumentException when creating ExceptionStackEvent.
This exception will break the exception propagation.

Generally, I'm also a bit confused by the exception handler setup, it looks like there is a application global instance held by the exception handler factory. Besides I don't think this is thread safe and the spec says ExceptionHandlers are request scoped - if there is an error while processing the exception or there is no other ExceptionHandler defined (e.g. Myfaces without org.apache.myfaces.ERROR_HANDLING=true) exceptions will not be removed and indefinitely delivered (ExceptionHandlerBroadcaster throws without marking as handled if there are no deltaspike handlers) for unrelated requests.