Single Inheritance in Java

Benefits of of Single Inheritance in Java

• It makes code easier to understand and manage by maintaining a hierarchical structure. Code duplicity is also reduced.
• Code reusability, as a derived class, can inherit the properties, behaviours and methods from the parent class.
• A higher level of abstraction, as the derived class can add its own methods and properties with the addition of the properties inherited from the parent class.

Limitations of of Single Inheritance in Java

• a class can only inherit from a single parent which results in less flexibility for class designs.
• limit the ability to reuse code as some code might not fit in a hierarchy caused due to single inheritance.
• This can cause ambiguity in code or throw errors, as some inherited methods can have the same names but have different operations.

Examples of Single Inheritance in Java Programming

Let us take two examples of single inheritance:

Example 1:

• Java

Java

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

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

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

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Output:

Example 2:

• Java

Java

class Shape {
    void draw() {
        System.out.println("Drawing a shape");
    }
}

class Circle extends Shape {
    void drawCircle() {
        System.out.println("Drawing a circle");
    }
}

public class Main {
    public static void main(String[] args) {
        Circle myCircle = new Circle();
        myCircle.draw(); // Inherited from Shape
        myCircle.drawCircle();
    }
}

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Output:

Using Super() and Subclass Constructors in Single Inheritance in Java

In Java, when implementing single inheritance, the super() keyword is used in a subclass constructor to invoke the constructor of its superclass. This is crucial for initializing inherited attributes and ensuring proper construction of the object hierarchy.

Consider the following example:

• Java

Java

class Animal {
    String sound;

    Animal(String sound) {
        this.sound = sound;
    }

    void makeSound() {
        System.out.println("Animal makes a sound: " + sound);
    }
}

class Dog extends Animal {
    String breed;

    Dog(String sound, String breed) {
        super(sound); // Invoking superclass constructor
        this.breed = breed;
    }

    void displayInfo() {
        System.out.println("Dog breed: " + breed);
    }
}

class Main {
    public static void main(String[] args) {
        Dog myDog = new Dog("Woof", "Labrador");
        myDog.makeSound(); // Inherited from Animal
        myDog.displayInfo();
    }
}

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Output

In this example, the Dog class extends the Animal class. The super(sound) line in the Dog constructor invokes the constructor of the Animal class, initializing the sound attribute. This demonstrates the use of super() and subclass constructors in the context of single inheritance in Java.

Frequently Asked Questions

What is a real life example of single inheritance in Java?

An example is a "Car" class inheriting from a "Vehicle" class. The "Car" class gains properties like speed and methods like start() from the "Vehicle" class.

What is inheritance single & multilevel in Java?

Single inheritance involves a class inheriting from one superclass, while multilevel inheritance includes a chain of classes, each extending the one above it. In Java, this forms a hierarchy facilitating code organization and reuse.

What are the 4 types of inheritance in Java?

The four types of inheritance in Java are single, multilevel, hierarchical, and hybrid. Single, multilevel, and hierarchical are straightforward, while hybrid involves combining these types, typically using interfaces.

Conclusion

In this article, we discussed Single Inheritance in Java, an important concept in Object-oriented programming, how it works, the syntax, and examples of implementing single inheritance in Java. 

You can learn more about Object-Oriented Programming and related concepts here.

• Has-A Relationship in Java
• Super Keyword In Java
• Fibonacci Series in Java
• Delegation Event Model in Java
• Swap Function in Java
• Access modifiers in java

You can also learn programming in java from scratch from our guided path -” Basics of Java,” which explains everything needed to get started with programming in java, like functions, loops,  arrays, strings, and other Data Structures and Algorithms. 

Don’t forget to test your problem-solving skills by practicing problems from Coding Ninjas Studio, and also check out some Java Interview Questions as well as the numerous interview experiences specially curated to give you the right guidance.

Happy Coding!