Java Runtime Polymorphism - The Coding Shala

Home >> Learn Java >> Java Runtime Polymorphism

Java Runtime Polymorphism

Polymorphism means many forms. There are two types of polymorphism in Java:
  • compile-time polymorphism
  • Runtime polymorphism
Compile-time polymorphism is achieved by overloading and Runtime polymorphism is achieved by method overriding. We will see Runtime polymorphism in this chapter.

Runtime polymorphism is also known as Dynamic Method Dispatch. Runtime polymorphism is a process in which a call to an overridden method is resolved at runtime, not at the compile-time.

An overridden method is called through the reference variable of a superclass. We use upcasting for runtime polymorphism.

Upcasting

If the reference variable of Parent class refers to the object of Child class, it is known as upcasting.
Java Runtime Polymorphism - The Coding Shala
The following code shows how to achieved runtime polymorphism using upcasting. 

class Parent{}
class Child extends Parent{}
Parent p = new Child();//upcasting

Example of Java Runtime Polymorphism

This following example explains java runtime polymorphism: 

//Runtime polymorphism example
//thecodingshala.com 

class Parent{
    void Display(){
        System.out.println("Inside Parent class");
    }
}

class Child extends Parent{
    void Display(){
        System.out.println("Inside Child class");
    }
}

class GrandChild extends Child{
    void Display(){
        System.out.println("Inside GrandChild class");
    }
}

class Main{
    public static void main(String[] args){
        Parent p1 = new Parent();
        p1.Display();
        
        Parent p2 = new Child(); //upcasting
        p2.Display(); //override 
        
        Parent p3 = new GrandChild();
        p3.Display(); //works on multilevel inhertance also 
    }
}
Output:

Inside Parent class
Inside Child class
Inside GrandChild class

Java Runtime Polymorphism with Data Member

In Java, we can override a method but not the data members so runtime polymorphism can not be achieved by data members. The following example explains it: 

///runtime polymorphism with data member
//thecodingshala

class Parent{
    int num = 10;
}

class Child extends Parent{
    int num = 30;
}

class Main{
    public static void main(String[] args){
        Parent p = new Child();
        System.out.println(p.num);
    }


}
Output:

10


Other Posts You May Like
Please leave a comment below if you like this post or found some error, it will help me to improve my content.
By

Comments

Post a Comment

Popular Posts from this Blog

Java Program to Convert Binary to Decimal - The Coding Shala

Home >> Java Programs >> Convert Binary to Decimal  Hey there, welcome back to another post. In this post, we will learn how to convert Binary to Decimal in Java. Java Program to Convert Binary to Decimal You have given a binary number, convert it to a decimal number. Example:  Input: 101 Output: 5 Input: 111 Output: 7 Binary to Decimal Conversion in Java Approach We will the below formula to convert binary to decimal: decimal number = (2^0) * (rightmost digit) + (2^1) * (second rightmost digit) + ...  for example:  binary number = 110 decimal number = 2^0 * 0 + 2^1 * 1 + 2^2 * 1 = 1 * 0 + 2 * 1 + 4 * 1 = 0 + 2 + 4 = 6 Java Program:  import java.util.Scanner; /** * https://www.thecodingshala.com/ */ public class Main { public static void printDecimal( int num) { int decimal = 0; int twos = 1; // 2^0 = 1 initial value while (num > 0) { int temp = num
Read more

N-th Tribonacci Number Solution - The Coding Shala

Home >> Programming >> N-th Tribonacci Number  Hey there, welcome back to another post. In this post, we will learn how to solve the N-th Tribonacci Number problem and will implement its solution in Java. N-th Tribonacci Number Problem Statement The Tribonacci sequence Tn is defined as follows: T0 = 0, T1 = 1, T2 = 1, and Tn+3 = Tn + Tn+1 + Tn+2 for n >= 0. Given n, return the value of Tn.  Example 1:  Input: n = 4 Output: 4 Explanation: T_3 = 0 + 1 + 1 = 2 T_4 = 1 + 1 + 2 = 4 N-th Tribonacci Number Java Solution using Bottom-Up DP This problem is similar to the Fibonacci series. We can solve it using the Bottom-Up approach of dynamic programming. Time Complexity: O(n) Space Complexity: O(n) The space complexity can be reduced to O(1) by using variables to store the previous three values instead of using an array. Java Program:  class Solution { public int tribonacci( int n) { if (n == 0) return 0; if (n == 1 || n == 2
Read more

Shell Script to Create a Simple Calculator - The Coding Shala

Home >> Scripting >> simple calculator Shell Script to Create a Simple Calculator Write a shell script to create a simple calculator using a switch-case statement? Code:  #! / bin / bash echo "simple calculator" sum = 0 i = "y" echo "enter first number" read n1 echo "enter second number" read n2 while [ $ i = "y" ] do echo "1.Addition" echo "2.Subtraction" echo "3.Multiplication" echo "4.Division" echo "Enter choice" read ch case $ch in 1 ) sum =$(echo " $n1 + $n2" | bc - l) echo "Addition is =" $ sum ;; 2 ) sum =$(echo "$n1 - $n2" | bc - l) echo "Sub is =" $ sum ;; 3 ) sum =$(echo "$n1 * $n2" | bc - l) echo "Mul is =" $ sum ;; 4 ) sum =$(echo "$n1 / $n2" | bc - l) echo "div is =" $ sum ;; * )echo "invalid choice" esac echo "Do y
Read more

Shell Script to find sum, product and average of given numbers - The Coding Shala

Home >> Scripting >> Sum, product and average Shell Script to find the sum, product, and the average of given numbers Read four integer numbers from the user and find the sum, product, and average of these four numbers? Code:  #! / bin / bash echo "enter four integers" read a b c d sum =$(echo "$a + $b + $c + $d" | bc - l) average=$(echo "$sum / 4" | bc - l) product=$(echo "$a * $b * $c * $d" | bc - l) echo "sum = $sum" echo "Average = $average" echo "Product = $product" Other Posts You May Like Shell script to print sum of the digits of a number Shell Script to print number in descending order Shell script to find out biggest number from three numbers Shell script to find out factorial of a number Shell Script to create a simple calculator Please leave a comment below if you like this post or found some error, it will help me to improve my content.
Read more

Java Program to Convert Decimal to Binary - The Coding Shala

Home >> Java Programs >> Convert Decimal to Binary  Hey there, welcome back to another post. In this post, we will learn how to convert decimal to binary in Java. Java Program to Convert Decimal to Binary You have given a decimal number. Write a Java program to convert decimal to binary. Example 1:  Input: 7 Output: 111 Input: 10 Output: 1010 Decimal to Binary Conversion using Array Approach To convert decimal to binary we can follow the below steps: Store the remainder in the array when we divide the number by 2. Divide the number by 2. Follow the above two steps until the number is above 0. Print the array in reverse order. For example:  4 % 2 = 0 => 4/2 = 2 2 % 2 = 0 => 2/2 = 1 1 % 2 = 1 => 1/2 = 0 Binary of 4 is: 100 Java Program:  import java.util.ArrayList; import java.util.List; import java.util.Scanner; /** * https://www.thecodingshala.com/ */ public class Main { public static void printBinary( int num) {
Read more