It defines attributes and methods which implement the data structure and operations of the ADT, respectively. Instances of classes are called objects . Consequently, classes define properties and behaviour of sets of objects. We have talked of instances of abstract employees . We call these instances objects .
Objects are uniquely identifiable by a name .
Therefore you could have two distinguishable objects with the same set of values. We refer to the set of values at a particular time as the state of the object. An object is an instance of a class. It can be uniquely identified by its name and it defines a state which is represented by the values of its attributes at a particular time. The state of the object changes according to the methods which are applied to it.