🧾 Java OOPs Scenario-Based Programming Questions (50 Questions) - Ajay Dabade

🔹 Section A: Classes & Objects

Q1. (Scenario Based)

A college wants to manage student information.
Write a Java program to:

Create a class Student
Include data members: id, name, marks
Add a method to display student details
Create at least 3 student objects and display their data

Q2. (Scenario Based)

A company needs to store employee details.
Write a Java program to:

Create a class Employee
Store empId, name, salary
Display employee details using a method

Q3. (Scenario Based)

A construction company wants to calculate area of plots.
Write a Java program to:

Create a class Rectangle
Add methods to calculate area and perimeter
Display results

Q4. (Scenario Based)

A sports academy tracks player performance.
Write a Java program to:

Create a class Player
Store player name and score
Display player details

Q5. (Scenario Based)

A library wants to manage books.
Write a Java program to:

Create a class Book
Include title, author, price
Display book information

🔹 Section B: Constructors

1. Constructor with Validation and Method Logic

Create a class Student with:

Attributes: name (String), marks (int)
Constructor to initialize values (marks must be 0–100, else set to -1)
Method getGrade() that returns:
- A (≥90), B (≥75), C (≥50), F (<50)

Task: Create multiple students and print their grades.

2. Constructor Overloading with Business Logic

Create a class Product with:

Attributes: productId, name, price, discount
Constructors:
- One without discount (default = 0)
- One with discount
Method finalPrice() that calculates price after discount

Task: Show final price for different products.

3. Copy Constructor with Deep Copy Concept

Create a class Address with:

Attributes: city, pincode
Create another class Employee with:
Attributes: name, Address address
Parameterized constructor
Copy constructor (ensure deep copy, not reference copy)

Task: Modify copied object’s address and verify original is unchanged.

4. Constructor Chaining with Calculation

Create a class Box with:

Attributes: length, width, height
Constructors:
- Default (1,1,1)
- Two parameters (height default = 1)
- Three parameters
Use constructor chaining
Method volume()

Task: Calculate volume for different objects.

5. Static Members with Constructor Logic

Create a class BankAccount with:

Attributes: accountNumber, balance
Static variable: totalAccounts
Constructor increments count and auto-generates account number
Method deposit(double amt)

Task: Track total accounts created.

6. Immutable Class Using Constructor

Create a class ImmutableStudent:

Private final attributes: name, rollNo
Initialize using constructor
Only getter methods, no setters

Task: Prove object cannot be modified after creation.

7. Constructor with Array Initialization

Create a class Library with:

Attribute: array of Book objects
Constructor initializes array with given size
Method to add book details and display all books

Task: Manage multiple books using constructors.

8. Constructor with Exception Handling

Create a class User with:

Attributes: username, password
Constructor:
- Username must not be empty
- Password must be at least 6 characters
Throw exception if invalid

Task: Handle invalid inputs using try-catch.

9. Constructor + Object Composition

Create a class Engine with:

Attributes: type, horsePower

Create a class Car with:

Attributes: brand, Engine engine
Constructor initializes both objects
Method displayCarDetails()

Task: Demonstrate object composition using constructors.

10. Constructor + Method Overloading + Logic

Create a class Calculator with:

Constructor prints “Calculator Initialized”
Overloaded methods:
- add(int a, int b)
- add(double a, double b)
Method multiply(int a, int b)

Task: Demonstrate constructor execution and method overloading.

🔹 Section C: Inheritance

Q11. (Scenario Based)

An animal simulation system needs common and specific behaviors.
Write a Java program to:

Create base class Animal
Derive class Dog
Display sound

Q12. (Scenario Based)

A company wants to manage employee hierarchy.
Write a Java program to:

Create classes Person and Employee
Inherit properties and display details

Q13. (Scenario Based)

A company has multiple levels of management.
Write a Java program to:

Implement multilevel inheritance (Person → Employee → Manager)

Q14. (Scenario Based)

A drawing application supports multiple shapes.
Write a Java program to:

Create base class Shape
Derive Circle and Rectangle
Calculate area

Q15. (Scenario Based)

A system needs to reuse parent class initialization.
Write a Java program to:

Use super keyword to call parent constructor

🔹 Section D: Method Overloading

Q16. (Scenario Based)

A system needs to perform different operations using the same method name.
Write a Java program to:

Create class Calculator
Overload method calculate() for:
- Adding two numbers
- Adding three numbers
Display results

Q17. (Scenario Based)

A geometry tool calculates area for different shapes.
Write a Java program to:

Overload method area() for circle and rectangle

Q18. (Scenario Based)

A student system stores different types of data.
Write a Java program to:

Overload method display() for different parameters

Q19. (Scenario Based)

A calculator handles different data types.
Write a Java program to:

Overload method for int, double

Q20. (Scenario Based)

A printing system needs multiple formats.
Write a Java program to:

Overload method print()

🔹 Section E: Method Overriding

Q21. (Scenario Based)

An animal system needs specific sound behavior.
Write a Java program to:

Override method sound() in subclass

Q22. (Scenario Based)

A vehicle system needs different running behavior.
Write a Java program to:

Override method run() in subclass

Q23. (Scenario Based)

A system needs runtime decision for method execution.
Write a Java program to:

Demonstrate runtime polymorphism

Q24. (Scenario Based)

A company customizes behavior of inherited methods.
Write a Java program to:

Use @Override annotation

Q25. (Scenario Based)

A system wants to extend parent functionality.
Write a Java program to:

Override method and call parent method using super

🔹 Section F: Polymorphism

Q26. (Scenario Based)

A payroll system calculates salary differently for employees.
Write a Java program to:

Create class Employee
Subclasses: FullTime, PartTime
Use dynamic method dispatch

Q27. (Scenario Based)

A system processes different types of payments.
Write a Java program to:

Use parent reference for multiple payment types

Q28. (Scenario Based)

A system handles different object types using one reference.
Write a Java program demonstrating upcasting

Q29. (Scenario Based)

A system needs access to child-specific methods.
Write a Java program demonstrating downcasting

Q30. (Scenario Based)

A system needs flexible method execution.
Write a Java program using runtime polymorphism

🔹 Section G: Encapsulation

Q31. (Scenario Based)

A bank needs to protect customer data.
Write a Java program to:

Create class BankAccount
Use private variables
Provide deposit and withdraw methods

Q32. (Scenario Based)

A system restricts direct access to data.
Write a Java program using getters and setters

Q33. (Scenario Based)

A system validates user input.
Write a Java program to:

Add validation in setter method

Q34. (Scenario Based)

A company hides internal data from users.
Write a Java program demonstrating data hiding

Q35. (Scenario Based)

A system ensures controlled access to variables.
Write a Java program using encapsulation

🔹 Section H: Abstraction

Q36. (Scenario Based)

A drawing system defines common structure for shapes.
Write a Java program to:

Create abstract class Shape
Define abstract method area()

Q37. (Scenario Based)

A vehicle system defines common operations.
Write a Java program using abstract class

Q38. (Scenario Based)

A system uses both abstract and concrete methods.
Write a Java program demonstrating abstract class

Q39. (Scenario Based)

A payroll system needs flexible salary calculation.
Write a Java program using abstract class Employee

Q40. (Scenario Based)

A system models real-world abstraction.
Write a Java program using abstract class

🔹 Section I: Interfaces

Q41. (Scenario Based)

A system defines common behavior for vehicles.
Write a Java program to:

Create interface Vehicle
Implement in Car and Bike

Q42. (Scenario Based)

A system requires multiple capabilities.
Write a Java program to:

Implement multiple interfaces

Q43. (Scenario Based)

A system extends interface functionality.
Write a Java program demonstrating interface inheritance

Q44. (Scenario Based)

A system uses default functionality in interfaces.
Write a Java program using default methods

Q45. (Scenario Based)

A system simulates multiple inheritance.
Write a Java program using interfaces

🔹 Section J: Integrated Real-World Problems

Q46. (Scenario Based)

A library wants to manage books and users.
Design a Java program using OOP principles

Q47. (Scenario Based)

A school needs a result management system.
Design using classes and inheritance

Q48. (Scenario Based)

A bank needs a complete account management system.
Design using encapsulation and inheritance

Q49. (Scenario Based)

An e-commerce system processes different payment methods.
Design using polymorphism

Q50. (Scenario Based)

A vehicle rental company needs a system to manage vehicles and bookings.
Design using OOP concepts