Inheritance in java

Inheritance

Inheritance is a process of deriving a new class from existing class. The new class gets properties and methods inherited from existing class.

super class

It is a class from which a new class inherits properties and methods. It is also known as base class or parent class or super class.

Sub Class

It is a class, which is derived from an existing class. It is class known as child class or derived class.

Why use inheritance in java

• For Method Overriding ( polymorphism).
• For Code Reusability.

Types of Inheritance  

1. Single inheritance
2. Multiple inheritance
3. Multi level inheritance
4. Hierarchical inheritance

Syntax of Java Inheritance

Class subclass-name  extends superclass-name{ }

The extends keyword indicates that you are making a new class that derives from an existing class.

Single inheritance

It is a process of deriving a new class from a single base class.When a class inherits another class, it is known as a single inheritance.

Example:

class a{     void j1(){     System.out.println("java");     } } class b extends a{     void j2(){     System.out.println("python");        } }   public class Pairosoft{     public static void main(String[] args){       b obj=new b();       obj.j1();       obj.j2();      } }

Output:

java python

Multiple inheritance

It is a process of deriving a new class from more than one base class.

Syntax:

class A                 {                                 statements ;                 }                 class B                 {                                 statements ;                 }                 class C extends A, B                 {                                 statements ;                 }

NOTE:

          Java does not support multiple inheritance with classes. But, it supports multiple inheritance using interfaces.

Multi level inheritance

It is a process of deriving a new class from another deriving class.When there is a chain of inheritance, it is known as multilevel inheritance.

Example:

class a{     void j1(){     System.out.println("java");     } } class b extends a{     void j2(){     System.out.println("python");        } } class c extends b{     void j3(){     System.out.println("c++");     } } public class Pairosoft{     public static void main(String[] args){       c obj=new c();       obj.j1();       obj.j2();       obj.j3();     } }

Output:

java python c++

Hierarchical inheritance

It is a process of deriving more than one class from a single base class.

Example:

class a{     void j1(){     System.out.println("java");     } } class b extends a{     void j2(){     System.out.println("python");        } } class c extends a{     void j3(){     System.out.println("c++");     } } public class Pairosoft{     public static void main(String[] args){       c obj=new c();       obj.j1();       //obj.j2(); error       obj.j3();     } }

Output:

Java c++

 

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