In order to interact, other objects must send messages to an object's interface that will cause the object to perform a function that will have a known effect. See also entry under 2.3 Messages . Identity, Equality, Copy Smalltalk provides unique identity for all objects. A class is a group of objects that represent the same type of entity and share the same methods. A class describes the implementation of a set of similar objects.
Classes are themselves objects.
All objects belong to some class and an object is an instance of the class of which it belongs. Inheritance and Delegation Smalltalk class relationships are defined in terms of inheritance. In inheritance, the inheriting class is called the subclass and the class being inherited from is call the superclass. A subclass inherits all of its superclass' variables and methods. Instances can be implemented any non-abstract class.