Use of Object Diagram in UML?

An object diagram models the instances of classes in a class diagram. It contains objects and links interfacing with the related objects.

 Object diagrams permit us to demonstrate the static design view or static process view. It includes modeling a depiction of the framework which contains objects (instances), their state and joins between objects. This diagram represents the inactive portion of an interaction containing the objects that communicate and the joins between them without any messages. 

 Sample Object Diagram,