Object   An object represents a distinct instance of a class. It has unique identity as well as attribute values, which determine its state at any point in time. An object can exhibit behavior, but only as a result of being an instance of a class. An object is an instance of one and only one class.

Explanation

An object is a specific example (instance) of a class. While a class describes something from a generic point of view an object describes or represents an actual or specific example of the thing. In our natural language we use this idea regularly when we say, "a book we looked at yesterday" we are not referring to a particular book. However when we say, "the book we looked at yesterday", we are speaking of a specific book. This is part of what is known as the UML type-instance dichotomy, which occurs with many of the UML elements. The concept of a model is about abstraction or saying something general that applies equally to each one in a set of specific things.

Important Points

An object can have an identity and attribute values. These help to identify the object and show its state or condition.

An object can have an identity and attribute values. The identity distinguishes it from other objects that are instances of the same class or classes. The attribute values are values of the class attributes from which it is derived.

Related Entries

Class  Classifier,  Graphically Similar A class is related to a class instance because it is the classifier from which the instance is derived. A class represents a description of the set of things, whereas the class instance represents a specific element from the set.