Java Inheritance Practice Questions with Solutions

Inheritance is one of the four fundamental pillars of Object-Oriented Programming (OOP) in Java. It allows one class to inherit the properties (variables) and behaviors (methods) of another class, promoting code reusability, maintainability, and hierarchical relationships.

Using inheritance, developers can avoid writing the same code repeatedly by reusing existing classes.

Java supports the IS-A relationship through inheritance.

For example:

• A Car is a Vehicle.
• A Dog is an Animal.
• A Student is a Person.

In Java, inheritance is implemented using the extends keyword.

Example:

class Animal {

    void eat() {

        System.out.println("Animal is Eating");

    }

}

class Dog extends Animal {

    void bark() {

        System.out.println("Dog is Barking");

    }

}

Here:

• Animal → Parent Class (Superclass)
• Dog → Child Class (Subclass)

The Dog class automatically inherits the eat() method from the Animal class. Java Inheritance practice questions with solutions help to understand the concepts.

Types of Inheritance in Java

Java supports the following inheritance types:

• Single Inheritance
• Multilevel Inheritance
• Hierarchical Inheritance

Java does not support Multiple Inheritance using classes to avoid ambiguity (Diamond Problem). However, it supports multiple inheritance through interfaces.

Inheritance is widely used in:

• Banking Applications
• Hospital Management Systems
• Android Development
• Enterprise Applications
• Spring Boot Projects
• Game Development
• Desktop Software

In this chapter, you’ll solve practical Java inheritance programs frequently asked in interviews and coding assessments.

1. Java Program to Demonstrate Single Inheritance

Problem Statement

Write a Java program to demonstrate Single Inheritance where a child class inherits methods from its parent class.

Java Solution

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 dog = new Dog();

        dog.eat();

        dog.bark();

    }

}

Sample Output

Animal is Eating
Dog is Barking

Explanation

The Dog class inherits the eat() method from the Animal class using the extends keyword.

As a result, the Dog object can access both:

• Parent Class Method
• Child Class Method

Concepts Covered

• Single Inheritance
• Parent Class
• Child Class
• extends Keyword

2. Java Program to Demonstrate Multilevel Inheritance

Problem Statement

Write a Java program to demonstrate Multilevel Inheritance.

Java Solution

class Animal {

    void eat() {

        System.out.println("Animal is Eating");

    }

}

class Dog extends Animal {

    void bark() {

        System.out.println("Dog is Barking");

    }

}

class Puppy extends Dog {

    void weep() {

        System.out.println("Puppy is Weeping");

    }

}

public class Main {

    public static void main(String[] args) {

        Puppy puppy = new Puppy();

        puppy.eat();

        puppy.bark();

        puppy.weep();

    }

}

Sample Output

Animal is Eating
Dog is Barking
Puppy is Weeping

Explanation

Inheritance occurs across multiple levels.

Animal
   ↓
 Dog
   ↓
Puppy

The Puppy class inherits methods from both Dog and Animal.

Concepts Covered

• Multilevel Inheritance
• Parent Class
• Child Class
• Inherited Methods

3. Java Program to Demonstrate Hierarchical Inheritance

Problem Statement

Write a Java program to demonstrate Hierarchical Inheritance.

Java Solution

class Animal {

    void eat() {

        System.out.println("Animal is Eating");

    }

}

class Dog extends Animal {

    void bark() {

        System.out.println("Dog is Barking");

    }

}

class Cat extends Animal {

    void meow() {

        System.out.println("Cat is Meowing");

    }

}

public class Main {

    public static void main(String[] args) {

        Dog dog = new Dog();

        Cat cat = new Cat();

        dog.eat();

        dog.bark();

        System.out.println();

        cat.eat();

        cat.meow();

    }

}

Sample Output

Animal is Eating
Dog is Barking

Animal is Eating
Cat is Meowing

Explanation

Both Dog and Cat inherit from the same parent class Animal.

      Animal
      /    \
    Dog    Cat

Each child class has access to the parent class methods while also defining its own unique behavior.

Concepts Covered

• Hierarchical Inheritance
• Parent Class
• Multiple Child Classes
• Code Reusability

4. Java Program to Use the super Keyword

Problem Statement

Write a Java program to demonstrate the use of the super keyword for accessing a parent class method.

Java Solution

class Animal {

    void sound() {

        System.out.println("Animal makes a sound");

    }

}

class Dog extends Animal {

    void sound() {

        System.out.println("Dog barks");

    }

    void display() {

        super.sound();

        sound();

    }

}

public class Main {

    public static void main(String[] args) {

        Dog dog = new Dog();

        dog.display();

    }

}

Sample Output

Animal makes a sound
Dog barks

Explanation

The super keyword refers to the immediate parent class.

In this example:

• super.sound() calls the parent class method.
• sound() calls the child class method.

This is useful when the child class overrides a parent method but still needs to access the original implementation.

Concepts Covered

• super Keyword
• Method Overriding
• Parent Class Method
• Child Class Method

5. Java Program to Call Parent Class Constructor Using super()

Problem Statement

Write a Java program to demonstrate how the super() constructor is used to call the parent class constructor.

Java Solution

class Animal {

    Animal() {

        System.out.println("Animal Constructor Called");

    }

}

class Dog extends Animal {

    Dog() {

        super();

        System.out.println("Dog Constructor Called");

    }

}

public class Main {

    public static void main(String[] args) {

        Dog dog = new Dog();

    }

}

Sample Output

Animal Constructor Called
Dog Constructor Called

Explanation

The super() statement calls the constructor of the parent class before executing the child class constructor.

If super() is not written explicitly, Java automatically inserts it as the first statement of the child constructor (provided the parent has a no-argument constructor).

This ensures that the parent object is initialized before the child object.

Concepts Covered

• super() Constructor
• Constructor Chaining
• Parent Constructor
• Child Constructor

6. Java Program to Demonstrate Method Overriding

Problem Statement

Write a Java program to demonstrate Method Overriding, where a child class provides its own implementation of a parent class method.

Java Solution

class Animal {

    void sound() {

        System.out.println("Animals make different sounds.");

    }

}

class Dog extends Animal {

    @Override
    void sound() {

        System.out.println("Dog says: Bark Bark");

    }

}

public class Main {

    public static void main(String[] args) {

        Dog dog = new Dog();

        dog.sound();

    }

}

Sample Output

Dog says: Bark Bark

Explanation

Method overriding occurs when a child class defines a method with the same name, return type, and parameters as the parent class.

When the overridden method is called, the child class version executes.

The @Override annotation tells the compiler that the method is intentionally overriding a parent method.

Concepts Covered

• Method Overriding
• Inheritance
• Runtime Polymorphism
• @Override Annotation

7. Java Program to Access Parent Class Variables

Problem Statement

Write a Java program to access variables inherited from a parent class.

Java Solution

class Person {

    String name = "Rahul Kumar";

}

class Student extends Person {

    int rollNumber = 101;

    void display() {

        System.out.println("Name        : " + name);

        System.out.println("Roll Number : " + rollNumber);

    }

}

public class Main {

    public static void main(String[] args) {

        Student student = new Student();

        student.display();

    }

}

Sample Output

Name        : Rahul Kumar
Roll Number : 101

Explanation

The child class automatically inherits public and protected variables from the parent class.

Here, the Student class accesses the inherited name variable directly without redefining it.

Concepts Covered

• Parent Class Variables
• Child Class
• Variable Inheritance
• Object-Oriented Programming

8. Java Program to Demonstrate Constructor Chaining

Problem Statement

Write a Java program to demonstrate Constructor Chaining using inheritance.

Java Solution

class Vehicle {

    Vehicle() {

        System.out.println("Vehicle Constructor");

    }

}

class Car extends Vehicle {

    Car() {

        System.out.println("Car Constructor");

    }

}

public class Main {

    public static void main(String[] args) {

        Car car = new Car();

    }

}

Sample Output

Vehicle Constructor
Car Constructor

Explanation

Whenever a child object is created, Java automatically calls the parent constructor first.

This process is called Constructor Chaining.

Execution order:

1. Parent Constructor
2. Child Constructor

Concepts Covered

• Constructor Chaining
• Parent Constructor
• Child Constructor
• Inheritance

9. Java Program to Create a Vehicle and Car Inheritance Example

Problem Statement

Write a Java program to create a Vehicle class and inherit it into a Car class.

Java Solution

class Vehicle {

    void startEngine() {

        System.out.println("Vehicle Engine Started");

    }

}

class Car extends Vehicle {

    void drive() {

        System.out.println("Car is Moving");

    }

}

public class Main {

    public static void main(String[] args) {

        Car car = new Car();

        car.startEngine();

        car.drive();

    }

}

Sample Output

Vehicle Engine Started
Car is Moving

Explanation

The Car class inherits the startEngine() method from the Vehicle class.

The child object can call both:

• Parent Method
• Child Method

This demonstrates code reuse using inheritance.

Concepts Covered

• Inheritance
• Vehicle Example
• Parent Class
• Child Class

10. Java Program to Create a Person and Student Inheritance Example

Problem Statement

Write a Java program where a Student class inherits the properties and methods of a Person class.

Java Solution

class Person {

    void displayPerson() {

        System.out.println("Person Information");

    }

}

class Student extends Person {

    void displayStudent() {

        System.out.println("Student Information");

    }

}

public class Main {

    public static void main(String[] args) {

        Student student = new Student();

        student.displayPerson();

        student.displayStudent();

    }

}

Sample Output

Person Information
Student Information

Explanation

The Student class inherits the displayPerson() method from the Person class while also defining its own displayStudent() method.

This demonstrates a simple IS-A relationship:

Person
   ↓
Student

Concepts Covered

• Parent Class
• Child Class
• Inheritance
• IS-A Relationship

11. Java Program to Demonstrate Hierarchical Inheritance with Employees

Problem Statement

Write a Java program to demonstrate Hierarchical Inheritance, where multiple child classes inherit from the same parent class.

Java Solution

class Employee {

    void companyName() {

        System.out.println("Company : ABC Technologies");

    }

}

class Developer extends Employee {

    void writeCode() {

        System.out.println("Developer writes Java code.");

    }

}

class Tester extends Employee {

    void testSoftware() {

        System.out.println("Tester performs software testing.");

    }

}

public class Main {

    public static void main(String[] args) {

        Developer developer = new Developer();

        Tester tester = new Tester();

        developer.companyName();
        developer.writeCode();

        System.out.println();

        tester.companyName();
        tester.testSoftware();

    }

}

Sample Output

Company : ABC Technologies
Developer writes Java code.

Company : ABC Technologies
Tester performs software testing.

Explanation

Both Developer and Tester inherit the companyName() method from the Employee class.

Each child class has its own additional method.

This demonstrates Hierarchical Inheritance.

Concepts Covered

• Hierarchical Inheritance
• Parent Class
• Multiple Child Classes
• Code Reusability

12. Java Program to Demonstrate Multilevel Inheritance with Animals

Problem Statement

Write a Java program to demonstrate Multilevel Inheritance using animal classes.

Java Solution

class Animal {

    void eat() {

        System.out.println("Animal Eats Food");

    }

}

class Mammal extends Animal {

    void walk() {

        System.out.println("Mammal Walks");

    }

}

class Dog extends Mammal {

    void bark() {

        System.out.println("Dog Barks");

    }

}

public class Main {

    public static void main(String[] args) {

        Dog dog = new Dog();

        dog.eat();
        dog.walk();
        dog.bark();

    }

}

Sample Output

Animal Eats Food
Mammal Walks
Dog Barks

Explanation

Inheritance flows across three levels.

Animal
   ↓
Mammal
   ↓
 Dog

The Dog class inherits methods from both Animal and Mammal.

Concepts Covered

• Multilevel Inheritance
• Parent Class
• Child Class
• Method Inheritance

13. Java Program to Demonstrate super Keyword for Variables

Problem Statement

Write a Java program to demonstrate the use of the super keyword for accessing parent class variables.

Java Solution

class Animal {

    String type = "Animal";

}

class Dog extends Animal {

    String type = "Dog";

    void display() {

        System.out.println("Child Variable  : " + type);

        System.out.println("Parent Variable : " + super.type);

    }

}

public class Main {

    public static void main(String[] args) {

        Dog dog = new Dog();

        dog.display();

    }

}

Sample Output

Child Variable  : Dog
Parent Variable : Animal

Explanation

The child class has its own variable named type.

Using:

super.type

allows access to the parent class variable.

Concepts Covered

• super Keyword
• Parent Variables
• Child Variables
• Variable Hiding

14. Java Program to Demonstrate Dynamic Method Dispatch

Problem Statement

Write a Java program to demonstrate Dynamic Method Dispatch.

Java Solution

class Animal {

    void sound() {

        System.out.println("Animal Sound");

    }

}

class Dog extends Animal {

    @Override
    void sound() {

        System.out.println("Dog Barks");

    }

}

public class Main {

    public static void main(String[] args) {

        Animal animal = new Dog();

        animal.sound();

    }

}

Sample Output

Dog Barks

Explanation

Although the reference variable is of type Animal, it points to a Dog object.

At runtime, Java executes the overridden method of the actual object.

This is known as Dynamic Method Dispatch or Runtime Polymorphism.

Concepts Covered

• Dynamic Method Dispatch
• Runtime Polymorphism
• Method Overriding
• Parent Reference

15. Java Program to Create a Real-World Banking Inheritance Example

Problem Statement

Write a Java program to create a simple banking inheritance example where a SavingsAccount inherits from a BankAccount.

Java Solution

class BankAccount {

    void accountType() {

        System.out.println("Bank Account");

    }

}

class SavingsAccount extends BankAccount {

    void interestRate() {

        System.out.println("Interest Rate : 6.5%");

    }

}

public class Main {

    public static void main(String[] args) {

        SavingsAccount account = new SavingsAccount();

        account.accountType();

        account.interestRate();

    }

}

Sample Output

Bank Account
Interest Rate : 6.5%

Explanation

The SavingsAccount class inherits the common functionality of the BankAccount class while adding its own specific feature (interest rate).

This is a practical example of inheritance in banking software.

Concepts Covered

• Real-World Inheritance
• Banking Example
• Parent Class
• Child Class
• Code Reusability

Chapter Summary

In this chapter, you learned one of the most powerful concepts of Object-Oriented Programming—Inheritance. Inheritance allows a child class to reuse the properties and methods of a parent class, reducing code duplication and making applications more modular and maintainable.

Throughout this chapter, you practiced various inheritance programs, including:

• Single Inheritance
• Multilevel Inheritance
• Hierarchical Inheritance
• Using the extends keyword
• Using the super keyword
• Calling parent class constructors with super()
• Accessing parent class variables
• Method Overriding
• Dynamic Method Dispatch (Runtime Polymorphism)
• Real-world examples such as Vehicle-Car, Person-Student, Employee-Developer, and Bank Account-Savings Account

Inheritance forms the base for advanced Java concepts such as Polymorphism, Abstract Classes, Interfaces, Method Overriding, and Framework Development.

Understanding inheritance is essential for Java interviews and enterprise application development because almost every large Java project uses inheritance to organize and reuse code efficiently.

Key Takeaways

• Inheritance allows one class to reuse another class’s properties and methods.
• The extends keyword is used to implement inheritance in Java.
• The parent class is also called the Superclass.
• The child class is also called the Subclass.
• Java supports:
  • Single Inheritance
  • Multilevel Inheritance
  • Hierarchical Inheritance
• Java does not support multiple inheritance using classes.
• The super keyword accesses parent class methods, variables, and constructors.
• Constructor chaining automatically initializes parent objects before child objects.
• Method Overriding enables Runtime Polymorphism.
• Inheritance improves code reusability, maintainability, and scalability.

Frequently Asked Questions (FAQs)

1. What is inheritance in Java?

Inheritance is an Object-Oriented Programming feature that allows one class to acquire the properties and methods of another class.

Example:

class Dog extends Animal

2. Which keyword is used for inheritance?

Java uses the extends keyword.

Example:

class Student extends Person

3. What is the difference between a parent class and a child class?

4. What is the super keyword?

The super keyword refers to the immediate parent class.

It can be used to:

• Access parent variables
• Access parent methods
• Call parent constructors

Example:

super.display();

5. What types of inheritance does Java support?

Java supports:

• Single Inheritance
• Multilevel Inheritance
• Hierarchical Inheritance

Java does not support multiple inheritance using classes because it can lead to ambiguity (Diamond Problem).

6. What is method overriding?

Method overriding occurs when a child class provides its own implementation of a method that already exists in the parent class.

It enables Runtime Polymorphism.

7. What is Dynamic Method Dispatch?

Dynamic Method Dispatch is Java’s mechanism for resolving overridden method calls at runtime based on the actual object type rather than the reference type.

Example:

Animal animal = new Dog();
animal.sound();

The Dog class’s sound() method is executed.

8. Why is inheritance important?

Inheritance helps developers:

• Reuse code
• Reduce duplication
• Improve maintainability
• Build scalable applications
• Model real-world relationships
• Support polymorphism
• Organize large projects efficiently

It is widely used in enterprise software, Android apps, banking systems, and web applications.

Written by Shubhranshu Shekhar, who has trained 20000+ students in coding.

Rishabh Kumar