An individual entity with its own identity and value. A classifier specifies the form and behavior of a set of instances with similar properties. An instance has identity and values that are consistent with the specification in the classifier. Instances appear in models as instance specifications.
See also classifier, identity, instance specification, link, object.
The UML specification document does not include a clear specification of the run-time environment that models describe. Without such a specification, models lack meaning. The following discussion probably should have been included in the specification. It represents the commonly accepted background without which models make little sense.
An instance is an entity ...