What is Inheritance?

• Inheritance is a mechanism in which one class (say child class or derived class) derives the properties i.e. methods and fields of another class(say a parent or base class) including itself.

Need of Inheritance

• Inheritance is mostly used to increase the reusability(using the same piece of code oftentimes) of code which makes the program efficient.
• Also to achieve runtime polymorphism(you will read further in detail)

Implementation of Inheritance

Syntax:

class child_class-name extends parent_class-name
{
     // your code
}

Example:

package quipohouse;

class Parent{
int a=10;

void parentMethod() {
System.out.println("Inside Parent Class");    
  }
}
class Child extends Parent{
int b=10;
void childMethod() {
System.out.println("Inside Child Class");
}
public static void main(String[] args) {

Child c=new Child();
c.childMethod();                                      //child method is invoked
c.parentMethod();                                     //parent method is invoked
System.out.println("field of child class-"+c.b);      //child class field
System.out.println("field of parent class-"+c.a);     //parent class field
   }
}

Output-

Inside Child Class
Inside Parent Class
field of child class-10
field of parent class-10

As in the above program, we can see then how the child class object is invoked by both the methods and fields of the parent class including itself.