Inheritance in Java Programming with examples

In this post. We are going to discuss:

• Introduction of Inheritance
• Types Of Inheritance
• Important Fact about inheritance

Introduction Of Inheritance in Java

the process by which one class acquires the data member (Variables) and member functions (methods) of other class that process is called inheritance. The main benefits of Inheritance are it provides the code reusability so that a class can extend the properties and behaviours of an existing class. After that, they need to write only the unique new features.

Important Terminology Of Inheritance

• Parent Class: A Class whose properties and member functions are inherited by another class is know a parent class, superclass or base class.
• Child Class: A Class who extends the properties and behaviours of other class is called child class, subclass or derived class.

Inheritance Syntax in Java

For Inherit the data member and member functions, we are using a keyword “Extends”. Suppose there are two classes (Class1 & Class2) present, where class2 inheriting the properties and methods of class1, Then we have to write like below

Class class2 extends class1
{
//Body
}

Types of Inheritance in Java

In Java, there are mainly five types of inheritance are there, that is:

• Single Inheritance
• Multi-Level Inheritance
• Hierarchical inheritance
• Hybrid Inheritance
• Multiple Inheritance

Single Inheritance in Java

In this type of inheritance, there are two classes present one is parent class and another one is child class. Here child class inherits the properties of parent class into child class. By this, we can reuse the existing code and also we can add new features in the child class.

Write the Program

Multi-Level Inheritance in Java

When a Class had more than one parent class, that type of inheritance is called multilevel inheritance. If you saw the pic, you can find that class b inherit member and methods of class a and Class c extend class b.

Add Pic & Program,

Hierarchical Inheritance in Java

This type of inheritance, one class is served as a base class, and multiple subclasses extend the features and methods of that base class. If you saw in the diagram, then Class A Is the base class and Class B, Class C, And Class D are the subclasses who extends Class A.

Add Pic & Program,

Multiple Inheritance in Java

In Multiple inheritances, one class have more than one base class, and it inherits features from all its parent class. But Java doesn’t support multiple inheritances with classes, But we can achieve multiple inheritances by implementing Interface.

Add Pic & Program,

Hybrid Inheritance in Java

The Combination of one or more above types of inheritance is called Hybrid inheritance.

Points to Remember

• Multiple Inheritance is Not allowed in Java: Multiple inheritances means a class has more than one parent class. Because of these features, there is a chance of ambiguity situation that’s why multiple inheritances are not permitted in Java.

Add Pic and Explanation
Note: Multiple inheritances are not permitted in Java, but you can achieve that by using Interface.

• Cyclic Inheritance Is not allowed: It is a type of inheritance where a class extends itself or by some loop. Such kind of inheritance is not allowed in Java because of this lead to ambiguity.

Add Pic and Explanation

• Private Members Are Not Inherited
  Add Pic and Explanation
• Constructors Cant Not Inherited In Java

Constructors can not be inherited in Java as the subclass have a different name. But when we are creating the object of the subclass that time default constructor of parent class called by default. It is all happening because when the child class constructor called, that time the first statement of a child class constructor is a super keyword that’s why when we create a child class object the parent class-default constructor also called automatically.

Because of the super keyword, we can call the parent class constructor other then this we are not permitted to call the parent class constructor directly.

Ref: article

Write a Program To Find Inheritance In Java With Example?

package com.java.Softwaretestingblog;
class A
{
    {
        System.out.println("In Class A");
    }
}
class B extends A
{
    {
        System.out.println("In Class B");
    }
}
class C extends B
{
    {
        System.out.println("In Class C");
    }
}
public class InheritanceDemoEx 
{
   public static void main(String[] args) 
   {
      @SuppressWarnings("unused")
      C obj=new C(); //Output Comes 123

   }
}

Execution: The Output link

Check Also: Compare Two Array In Java

Output:

In Class A
In Class B
In Class C