Abstract W3schools Code Example

Example 1: abstraction in java

Abstraction is defined as hiding internal implementation and showing only  necessary information. // abstract class abstract class Addition {    // abstract methods    public abstract int addTwoNumbers(int number1, int number2);    public abstract int addFourNumbers(int number1, int number2, int number3, int number4);    // non-abstract method    public void printValues()    {       System.out.println("abstract class printValues() method");    } } class AbstractMethodExample extends Addition {    public int addTwoNumbers(int number1, int number2)    {       return number1 + number2;    }    public int addFourNumbers(int number1, int number2, int number3, int number4)    {       return number1 + number2 + number3 + number4;    }    public static void main(String[] args)    {       Addition add = new AbstractMethodExample();       System.out.println(add.addTwoNumbers(6, 6));       System.out.println(add.addFourNumbers(8, 8, 3, 2));       add.printValues();    } }

Example 2: abstract class in java

Sometimes we may come across a situation where we cannot provide implementation to all the methods in a class. We want to leave the  implementation to a class that extends it.   In that case we declare a class as abstract by using abstract keyword on method signature.In my framework I have created my PageBase class as super class of the all page classes.  I have collected all common elements and functions into PageBase class and all other page classes extent PageBase class. By doing so, I don't have to locate very common WebElements and it provides reusability in my framework. Also 1)Abstract classes cannot be instantiated 2)An abstarct classes contains abstract method, concrete methods or both. 3)Any class which extends abstarct class must   override all methods of abstract class 4)An abstarct class can contain either   0 or more abstract method.