Question

1. What do you understand by polymorphism? Why are they useful? Explain each type of polymorphism using a clear example. [15 points]

Answer 1

Polymorphism is the ability to print output in one or more forms.it performs single action in different ways.

It will be useful in application where one interface multiple usage.

Polymorphism is divided into two types:

Compile type polymorphism and run time polymorphism

Compile type polymorphism:it also known static polymorphism,

This type of polymorphism is used in function overloading and operator overloading.

Example: void function (int a)

Void function (int a, int b)

Void function (int c)

When there are multiple functions with different parameters

1. Example: By using different types of arguments // Java program for Method overloading class MultiplyFun {     // Method with 2 parameter     static int Multiply(int a, int b)     {         return a * b;     }     // Method with the same name but 2 double parameter     static double Multiply(double a, double b)     {         return a * b;     } } class Main {     public static void main(String[] args)     {         System.out.println(MultiplyFun.Multiply(2, 4));         System.out.println(MultiplyFun.Multiply(5.5, 6.3));     } } Output: 8 34.65 Example: By using different numbers of arguments // Java program for Method overloading class MultiplyFun {     // Method with 2 parameter     static int Multiply(int a, int b)     {         return a * b;     }     // Method with the same name but 3 parameter     static int Multiply(int a, int b, int c)     {         return a * b * c;     } } class Main {     public static void main(String[] args)     {         System.out.println(MultiplyFun.Multiply(2, 4)); } } Operator Overloading: Java also provide option to overload operators. For example, we can make the operator (‘+’) for string class to concatenate two strings. We know that this is the addition operator whose task is to add two operands. So a single operator ‘+’ when placed between integer operands, adds them and when placed between string operands, concatenates them. In java, Only “+” operator can be overloaded: To add integers To concatenate strings Example: // Java program for Operator overloading class OperatorOVERDDN {     void operator(String str1, String str2)     {         String s = str1 + str2;         System.out.println("Concatinated String - "                            + s);     }     void operator(int a, int b)     {         int c = a + b;         System.out.println("Sum = " + c);     } } class Main {     public static void main(String[] args)     {         OperatorOVERDDN obj = new OperatorOVERDDN();         obj.operator(2, 3);         obj.operator("joe", "now");     } } Output: Sum = 5 Concatinated String - joenow Runtime polymorphism: It is also known as Dynamic Method Dispatch. It is a process in which a function call to the overridden method is resolved at Runtime. This type of polymorphism is achieved by Method Overriding. Method overriding, on the other hand, occurs when a derived class has a definition for one of the member functions of the base class. That base function is said to be overridden. Example: // Java program for Method overridding class Parent {     void Print()     {         System.out.println("parent class");     } } class subclass1 extends Parent {     void Print()     {         System.out.println("subclass1");     } } class subclass2 extends Parent {     void Print()     {         System.out.println("subclass2");     } } class TestPolymorphism3 {     public static void main(String[] args)     {         Parent a;         a = new subclass1();         a.Print();         a = new subclass2();         a.Print();