Inheritance in Java

Java 114 views Dec 01, 2025 2 min read

Inheritance is a fundamental concept of object-oriented programming (OOP) in Java. It allows one class (child/subclass) to acquire the properties and behaviors of another class (parent/superclass). Inheritance promotes code reuse, modularity, and extensibility.

1. Key Features of Inheritance

Enables a new class to reuse code from an existing class.
Supports hierarchical organization of classes.
Reduces redundancy and improves maintainability.
Facilitates polymorphism in Java.

2. Types of Inheritance in Java

(a) Single Inheritance

A subclass inherits from one superclass.

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

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

public class Test {
    public static void main(String[] args) {
        Dog d = new Dog();
        d.eat();  // Inherited method
        d.bark();
    }
}

(b) Multilevel Inheritance

A class inherits from a subclass, forming a chain of inheritance.

class Animal { void eat(){} }
class Mammal extends Animal { void walk(){} }
class Dog extends Mammal { void bark(){} }

(c) Hierarchical Inheritance

Multiple subclasses inherit from a single superclass.

class Animal { void eat(){} }
class Dog extends Animal { void bark(){} }
class Cat extends Animal { void meow(){} }

(d) Hybrid Inheritance

Combination of two or more types of inheritance.
Java does not support multiple class inheritance directly but supports it via interfaces.

3. The `super` Keyword

Refers to the parent class object.
Used to access parent class methods, variables, and constructors.

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

class Dog extends Animal {
    void eat() { System.out.println("Dog Eating..."); }
    void show() { super.eat(); }
}

4. Advantages of Inheritance

Code Reusability: Avoids writing duplicate code.
Method Overriding: Enables polymorphism.
Organized Structure: Easier maintenance and readability.
Extensibility: New features can be added without changing existing code.

5. Conclusion

Inheritance in Java allows a class to inherit properties and behaviors from another class, supporting the OOP principles of reusability, modularity, and extensibility. Proper use of inheritance simplifies program design and improves maintainability, making it a core concept in Java programming.

Some advanced sections are available for Registered Members

← Previous

Constructors in Java

Polymorphism in Java