UMLR — Provide exception handling for all behaviors.

UML2 has added the capability of dealing with exceptional behavior. Exception handling can occur at various levels of the model. Unfortunately, the exception handling mechanism has not been systematically developed. Any kind of behavior should support the mechanism of catching and handling an exception that was raised somewhere within that behavior. Unfortunately, currently only activities allow for this. Similar capabilities should be available for interactions and statemachines, and even for use cases. Recommendation: Provide exception handling for all behaviors.