An Object diagram is closely related to a Class diagram, with the distinction that it depicts object instances of Classes and their relationships at a point in time. This might appear similar to a Composite Structure diagram, which also models run-time behavior; the difference is that Object diagrams exemplify the static Class diagrams, whereas Composite Structure diagrams reflect run-time architectures different from their static counterparts.
Object diagrams do not reveal architectures varying from their corresponding Class diagrams, but reflect multiplicity and the roles instantiated Classes could serve.
|•||Object diagrams are useful in understanding a complex Class diagram, by creating different cases in which the relationships and Classes are applied|
|•||An Object diagram can also be a kind of Communication diagram (which also models the connections between objects, but additionally sequences events along each path)|
Example Diagram Example Object Diagram
Select Object diagram elements and connectors from the Object pages of the Toolbox.