Different Type Of Inheritance In Java

Different Type Of Inheritance In Java

Inheritance, a fundamental concept in object-oriented programming, empowers developers to create new classes that inherit attributes and behaviors from existing ones. Java, a versatile and widely used programming language, offers various types of inheritance mechanisms that facilitate code reusability and the construction of organized class hierarchies. Understanding these different types of inheritance is crucial for crafting efficient and maintainable Java applications. In this exploration, we delve into the diverse inheritance models provided by Java, examining how each type contributes to the architecture and design of software systems. From single and multiple inheritance to hierarchical and hybrid models, let’s embark on a journey to comprehend the intricacies of inheritance in Java.

What is Inheritance?

In the realm of Java programming, inheritance stands as a fundamental cornerstone, facilitating the passage of attributes and functionalities from one class to another—an analogy resembling the bond between a guardian and their ward. This intricate process, reminiscent of a father imparting his traits to his offspring, encapsulates the essence of inheritance: the art of transference.

In the Java landscape, the inheritance mechanism empowers creators to mold classes and characteristics with precision, catering to their distinct purposes. Notably, this concept traces its origins back to 1969, emerging within the Simula programming language at the Computing Center in Oslo. Though our focus is Java-centric, it’s important to recognize that the inheritance concept transcends linguistic boundaries, manifesting across renowned object-oriented languages such as PHP, C++, and Python. The term “inheritance” extends its reach beyond class structures, encompassing prototypes, and embodies a universally embraced paradigm.

As we embark on this journey, we will unravel the mosaic of inheritance in its entirety. Our expedition will navigate through the various facets of Java’s inheritance offerings, unearthing single and multiple inheritance nuances, delving into hierarchical constructs, and even exploring the uncharted terrain of hybrid models. Ultimately, we will gain a profound comprehension of how inheritance intricately weaves itself into the very fabric of software architecture, enriching the design of formidable and resilient systems.

Terminologies Related to the Concept are:

Class: Think of a class as a blueprint that outlines shared traits among objects. It lays the foundation for creating instances.

Subclass: This variant, also called a derived or extended subclass, inherits traits from another class. Beyond what it inherits, a subclass can add its own attributes and methods.

Superclass: The parent class, or superclass, contributes inheritable traits to subclasses, forming a hierarchical relationship.

Reusability: Reusability involves crafting new classes by incorporating methods from existing ones. It’s like building on a foundation, recycling code for efficiency.

Syntax

class derived_class extends base_class  

{  

//methods 

//fields

}

General Format

class​ superclass 

{ 

// superclass data variables 

// superclass member functions 

} 

class​ subclass ​extends​ superclass 

{ 

// subclass data variables 

// subclass member functions 

}

Note :

Inheritance uses the “extends” keywords in order to produce derived classes while using the Base class. Extending keywords indicates the class to another class. 

Types of Inheritance in Java

There are miscellaneous types of inheritance in java:

1. Single Inheritance
2. Multiple Inheritance
3. Multi-Level Inheritance
4. Hierarchical Inheritance
5. Hybrid Inheritance

Single Inheritance 

Single Inheritance: Single inheritance refers to the creation of a parent class from a sole base class. This approach involves utilizing just one class to establish the superclass. The beauty of single inheritance lies in the seamless utilization of superclass variables, subclass methods, and attributes, all coexisting without conflicts. This concept stands as a prominent type within the spectrum of inheritance in Java.

Here’s a simple coding example illustrating single inheritance in Java:

// Parent class
class Vehicle {
    void displayInfo() {
        System.out.println("This is a vehicle.");
    }
}

// Child class inheriting from the parent class
class Car extends Vehicle {
    void showDetails() {
        System.out.println("This is a car.");
    }
}

public class Main {
    public static void main(String[] args) {
        // Creating an object of the child class
        Car myCar = new Car();

        // Calling methods from both parent and child classes
        myCar.displayInfo(); // Method from the parent class
        myCar.showDetails(); // Method from the child class
    }
}

In this example, we have a Vehicle class as the parent class, and a Car class as the child class. The Car class inherits from the Vehicle class using single inheritance. The Car class can access the displayInfo() method from the Vehicle class, demonstrating the concept of single inheritance.

Multiple Inheritance

When a succession of diverse inheritances occurs, it’s referred to as multiple inheritance. Streamlining the creation of descendant classes from various parent classes defines the essence of multiple inheritance. This scenario could involve one or more superclass classes. While multiple inheritance is present in some object-oriented programming languages, it’s not a feature in Java and isn’t categorized as a type of inheritance in the Java context.

Java programmers often find intrigue in the concept of multiple inheritance, and while it’s not directly supported in Java, there’s an alternative approach using interfaces. Interfaces offer a means for Java programmers to emulate multiple inheritance in specific scenarios.

The absence of multiple inheritance in Java is attributed to the desire to avert ambiguity. Consider a scenario where class A extends class B, and both classes A and C implement the same method present in class B. This creates a potential conflict, making it difficult to ascertain which version of the method should be utilized. Java’s design choice to exclude multiple inheritance is rooted in maintaining code clarity and sidestepping such dilemmas.

Multi-Level Inheritance

Multilevel inheritance in Java involves the combination of two or more classes, where one class extends another, which in turn extends another class. This cascading relationship creates a sequence of parent and child classes. For instance, when there’s a class A extending class B, and class B extending class C, this configuration exemplifies multilevel inheritance.

Let’s explore this with an illustrative example using classes in the realm of food items:

class Food {
    void consume() {
        System.out.println("This is a generic food item.");
    }
}

class Pizza extends Food {
    void eat() {
        System.out.println("Enjoying a delicious pizza.");
    }
}

class CocaCola extends Pizza {
    void drink() {
        System.out.println("Sipping on a refreshing Coca-Cola.");
    }
}

public class Main {
    public static void main(String[] args) {
        CocaCola coke = new CocaCola();
        coke.consume(); // Method from the Food class
        coke.eat();    // Method from the Pizza class
        coke.drink();  // Method from the CocaCola class
    }
}

In this example, we have three classes: Food, Pizza, and CocaCola. The classes exhibit a multilevel inheritance structure. The CocaCola class extends the Pizza class, which in turn extends the Food class. This hierarchy allows the CocaCola class to inherit methods from both the Pizza and Food classes. This demonstration underscores the essence of multilevel inheritance and how it fits into the spectrum of inheritance types in Java.

Hierarchical Inheritance

Hierarchical inheritance in Java emerges when two or more child classes extend a shared parent class, creating a branching hierarchy. This scenario unfolds when a single parent class has multiple child classes extending from it. This configuration embodies the essence of hierarchical inheritance.

Let’s delve into this concept using a simple example in the context of vegetables:

class Vegetables {
    void displayType() {
        System.out.println("This is a vegetable.");
    }
}

class Potato extends Vegetables {
    void showVariety() {
        System.out.println("This is a type of potato.");
    }
}

class Tomato extends Vegetables {
    void revealColor() {
        System.out.println("This is a red tomato.");
    }
}

class Cucumber extends Vegetables {
    void describeShape() {
        System.out.println("This is a long cucumber.");
    }
}

public class Main {
    public static void main(String[] args) {
        Potato potato = new Potato();
        Tomato tomato = new Tomato();
        Cucumber cucumber = new Cucumber();

        potato.displayType();  // Method from the Vegetables class
        potato.showVariety();  // Method from the Potato class

        tomato.displayType();  // Method from the Vegetables class
        tomato.revealColor();  // Method from the Tomato class

        cucumber.displayType();  // Method from the Vegetables class
        cucumber.describeShape(); // Method from the Cucumber class
    }
}

In this example, the Vegetables class acts as the parent class, while Potato, Tomato, and Cucumber classes are child classes extending from it. This arrangement depicts hierarchical inheritance, as multiple classes branch out from a single parent class, each encapsulating distinct attributes and methods. This instance showcases how hierarchical inheritance aligns within the array of inheritance types in Java.

Hybrid Inheritance

Hybrid inheritance in Java refers to a blend of different inheritance types, combining elements of both single inheritance and multiple inheritances. However, it’s important to note that hybrid inheritance is not directly supported in Java due to potential complexities and ambiguities that could arise. Nevertheless, Java provides a way to achieve a similar effect using interfaces.

When discussing types of inheritance in Java, it’s important to clarify that hybrid inheritance is not a distinct category. Instead, it’s a combination of single inheritance and multiple inheritances, and as mentioned earlier, it’s not natively accommodated in Java due to concerns about code clarity and potential conflicts.

The two commonly recognized types of inheritance in Java are indeed single inheritance and hierarchical inheritance. Single inheritance involves one class inheriting from another, while hierarchical inheritance includes multiple subclasses extending from a single parent class. These concepts form the basis of inheritance in Java and are used to create organized class hierarchies and promote code reusability.

Inheritance Program in Java

Certainly! Here’s a simple inheritance program in Java that demonstrates the concept of single inheritance:

class Animal {
    void eat() {
        System.out.println("Animal is eating.");
    }
}

class Dog extends Animal {
    void bark() {
        System.out.println("Dog is barking.");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog myDog = new Dog();
        myDog.eat();  // Method inherited from the Animal class
        myDog.bark(); // Method from the Dog class
    }
}

In this program, we have a base class Animal with a method eat(). The Dog class extends the Animal class, inheriting the eat() method. The Dog class also has its own method bark(). In the Main class, we create an object of the Dog class and demonstrate how it can access both the inherited eat() method and its own bark() method.

This example showcases the principle of single inheritance, where a subclass inherits attributes and methods from a single superclass.

Applications of Inheritance in Java

Method Overriding in Java 

Method overriding in Java involves a subclass redefining a method from its superclass. The subclass method has the same name, parameters, and return type. This enables runtime polymorphism, where the actual method executed depends on the object’s type. Method overriding enhances inheritance by allowing subclasses to provide their own specialized behavior for inherited methods.

FAQ – Different Type Of Inheritance In Java