OMG-OCUP2-ADV300 Exam Dumps : OMG Certified UML Professional 2 (OCUP 2) - Advanced Level

In UML, ValueSpecifications are used to specify the value of an element. The UML 2 Specification does not define a metaclass named StringExpression. Instead, it provides a metaclass named OpaqueExpression, which can be used when an expression is written in a language that is not directly interpretable by the model. Since there is no metaclass called StringExpression in the UML 2 Specification, there is no explicitly intended use for it within the UML metamodel. The absence of this metaclass suggests that any use of a concept called "StringExpression" would not conform to standard UML 2 practices and would likely be part of an extension or profile, not the core UML metamodel.

For asynchronous invocations in UML, when an exception is thrown and there is no matching exception handler within the activity, the exception is effectively lost because there is no direct mechanism to propagate it back to the caller. This reflects the nature of asynchronous communication where the calling process does not wait for the completion of the called process and, thus, may not be designed to handle exceptions that occur during the called process.

References:

• UML 2.5 Specification: The UML specification describes the behavior of actions within activities and how exceptions are handled, or not handled, in the case of asynchronous calls. It specifically states that for asynchronous calls, the exception is not propagated back to the caller as there is no return flow defined for such invocations.

In the MOF class hierarchy, the class ‘Element’ sits at the top. It is the superclass of all classes defined in MOF and is an implicit superclass of all metaclasses defined using MOF1. This superclass relationship to ‘Element’ does not need to be explicitly declared in the metamodels.