The Use of Subtypes and Stereotypes in the UML Model

Based on users’ experiences of Version 1.3 of the Unified Modeling Language (UML) of the Object Management Group (OMG), a Request For Information in 1999 elicited several responses which were asked to identify “problems” but not to offer any solutions. One of these responses is examined for “problems” relating to the UML metamodel and here some solutions to the problems identified there are proposed. Specifically, we evaluate the metamodel relating to stereotypes versus subtypes; the various kinds of Classifier (particularly Types, Interfaces and Classes); the introduction of a new subtype for the whole-part relationship; as well as identifying areas in the metamodel where the UML seems to have been used inappropriately in the very definition of the UML’s metamodel.