Object-Orientated Design and Programming Unit 8: Inheritance and Polymorphism
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In Java an object reference that is declared of a particular class can 1166 polymorphism derived classes and dynamic bindings used to refer to an object of any subclass.
For example, in the TestPoly example below, the object reference s1 is declared as a reference of class Student. However, it can refer to instances of the MScStudent class as well as referring to instances of the Student class.
The term polymorphism can be defined as "having many forms". A polymorphic reference is a reference variable that can refer to different types of objects at different points in time as indicated by s1 in the TestPoly example. In the TestPloy example, we can see that there are two occurrences of s1.
If we run the TestPoly program, we get the following output:. This indicates that the first s1. The association of a method invocation to a method definition is called binding. For polymorphic references, the binding is performed at run time, i. Because a polymorphic reference may point to different types of objects over time, the binding between the method invocation and the appropriate definition needs to be determined at runtime based on the object that is being referred to 1166 polymorphism derived classes and dynamic bindings that moment in time.
An example of polymorphism is the technique by which a reference that is used to invoke a method can actually invoke different methods at different times depending on what it is referring to at the time. This can be illustrated by the following example. In the for loop, the want a free binary option demo accounts all[i]. Polymorphism provides a means to an elegant versatility in our software.
It allows us to provide a consistent approach to different but related behaviours. We should try to find opportunities in our software systems that lend themselves to polymorphic solutions. Object-Orientated Design and Programming Unit 8: Table of Contents Session Aims Inheritance Implementing inheritance in Java Superclasses and subclasses in Java An example of creating a subclass The protected modifier and visibility modifiers revisited Using the key word super and 1166 polymorphism derived classes and dynamic bindings superclass constructors Overriding methods in the superclass Dynamic binding, polymorphism via inheritance, and casting Casting Section summary End of unit student activity: Dynamic binding, polymorphism via inheritance, and casting In Java an object reference that is declared of a particular class can be used to refer to an object of any subclass.
If we run the TestPoly program, we get the following output: