Inheritance and its types in Java

Introduction :

Inheritance is a fundamental concept in object-oriented programming that allows the creation of new classes based on existing ones. Java, being an object-oriented language, provides robust support for inheritance. In this article, we will explore the concept of inheritance in Java, its benefits, and the different types of inheritance available. Understanding inheritance and its types will enable you to design flexible and modular code, promoting code reuse and creating class hierarchies.

Table of Contents:

1. Overview of Inheritance

2. Benefits of Inheritance

3. Syntax and Rules of Inheritance in Java

4. Single Inheritance

4.1. Creating Parent and Child Classes

4.2. Inheriting Fields and Methods

4.3. Overriding Methods in the Child Class

4.4. Accessing Superclass Members with "super"

8. Conclusion

1. Overview of Inheritance

Inheritance is a fundamental principle of object-oriented programming (OOP) that allows new classes to be created based on existing classes. In Java, inheritance enables the reuse of code and promotes the creation of class hierarchies. A class that is derived from another class is called a subclass or child class, while the class that is inherited from is called the superclass or parent class. The child class inherits the fields and methods of the parent class, allowing for code reuse and the extension of functionality.

2. Benefits of Inheritance:

Inheritance offers several benefits in Java programming:

a. Code Reuse: Inheritance allows classes to inherit fields and methods from a parent class, enabling code reuse and preventing redundancy. It promotes the DRY (Don't Repeat Yourself) principle.

b. Modularity and Organization: Inheritance provides a way to organize classes in a hierarchical manner. It allows for the creation of class hierarchies where classes are grouped based on common characteristics.

c. Polymorphism: Inheritance facilitates polymorphism, which allows objects of different classes to be treated uniformly. It promotes flexibility and extensibility in the code.

d. Easy Maintenance: With inheritance, modifications made in the parent class propagate to all its child classes. This makes it easier to maintain and update code.

3. Syntax and Rules of Inheritance in Java:

In Java, the "extends" keyword is used to establish inheritance between classes. The syntax for inheriting a class is as follows:

```java

class ChildClass extends ParentClass {

// class body

}

```

The child class extends the parent class, gaining access to its non-private fields and methods. Constructors, private members, and static members are not inherited. To inherit a class, the child class must have an "is-a" relationship with the parent class, meaning that

To inherit a class, the child class must have an "is-a" relationship with the parent class, meaning that the child class is a specific type of the parent class. The child class can then extend the functionality of the parent class by adding its own fields and methods or by overriding the parent class's methods.

4. Single Inheritance :

Single inheritance is the most common type of inheritance in Java, where a class extends a single parent class. Let's explore an example to understand single inheritance:

4.1. Creating Parent and Child Classes:

```java

class Vehicle {

protected String brand;

public void honk() {

System.out.println("Honk honk!");

}

}

class Car extends Vehicle {

private String model;

public Car(String brand, String model) {

this.brand = brand;

this.model = model;

}

public void displayCarInfo() {

System.out.println("Brand: " + brand);

System.out.println("Model: " + model);

}

}

```

4.2. Inheriting Fields and Methods:

In this example, the class "Car" extends the class "Vehicle" using the "extends" keyword. As a result, the "Car" class inherits the "brand" field and the "honk()" method from the "Vehicle" class.

4.3. Overriding Methods in the Child Class:

Child classes can override the methods of the parent class to provide their own implementation. For example, the "Car" class can override the "honk()" method:

```java

@Override

public void honk() {

System.out.println("Beep beep!");

}

```

4.4. Accessing Superclass Members with "super":

The "super" keyword is used to access members of the superclass from the child class. It is useful when you want to refer to the overridden method or access the superclass's constructor. For example, in the "displayCarInfo()" method of the "Car" class, we can use "super.brand" to access the "brand" field of the superclass.

In my next article will be the continuation of this article.

Thank you.

#programming #coding #java #code