⏱️ Time: 2 Hours
📊 Maximum Marks: 50

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📌 Instructions:

• Attempt all questions.
• Write each program in separate classes.
• Use proper OOP principles.
• Use Scanner class wherever input is required.
• Output must be clearly labeled.
• Add comments to explain your code.

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🔹 Section A – Core Programming (30 Marks)

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Q1. Class, Object & Constructor (10 Marks)

An online course platform wants to store and display course information.

👉 Write a Java program following the steps below:

1. Create a class named Course.
2. Declare the following instance variables:
   • courseId (int)
   • courseName (String)
   • duration (in hours, int)
   • fee (double)
3. Create a parameterized constructor:
   • It should accept values for all variables
   • Initialize them using the this keyword
4. Create a method named displayCourseDetails():
   • This method should print all course details in a proper format
   • Example: Course ID: 201
     Course Name: Java Programming
     Duration: 40 hours
     Fee: 5000.0
5. In the main() method:
   • Ask the user to enter details for 2 courses
   • Create objects using constructor
   • Display details of both courses

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Q2. Inheritance & Method Overriding (10 Marks)

A utility billing system calculates electricity bills differently for different consumers.

👉 Write a Java program as per the following instructions:

1. Create a base class ElectricityBill:
   • Method calculateBill(int units)
   • Default implementation should print: Bill calculation not defined
2. Create two subclasses:
   • DomesticUser
   • CommercialUser
3. Override the method in both classes:
   • DomesticUser:
     • Bill = units × ₹3
   • CommercialUser:
     • Bill = units × ₹5
4. In the main() method:
   • Ask user to enter number of units consumed
   • Create objects of both subclasses
   • Call the method and display bill
5. Output should clearly indicate:
   • Type of user
   • Units consumed
   • Total bill

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Q3. Encapsulation (10 Marks)

A payroll system must securely handle employee salary details.

👉 Write a Java program with the following requirements:

1. Create a class Payroll.
2. Declare private variables:
   • employeeId (int)
   • employeeName (String)
   • basicSalary (double)
3. Provide:
   • Getter and Setter methods
4. Add validation:
   • basicSalary should be greater than 0
   • If invalid, display "Invalid salary entered"
5. Create a method calculateNetSalary():
   • HRA = 20% of basic salary
   • DA = 10% of basic salary
   • Net Salary = basic + HRA + DA
6. In the main() method:
   • Create object
   • Set values using setters
   • Call method to calculate and display net salary

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🔹 Section B – Advanced OOP Concepts (20 Marks)

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Q4. Abstract Class (10 Marks)

A notification system sends alerts using different channels.

👉 Write a Java program as follows:

1. Create an abstract classNotification:
   • Abstract method sendNotification(String message)
2. Create subclasses:
   • EmailNotification
   • SMSNotification
3. Implement method:
   • Email → print "Sending Email: message"
   • SMS → print "Sending SMS: message"
4. In the main() method:
   • Use abstract class reference
   • Create objects of both subclasses
   • Call methods
5. Ensure:
   • Proper abstraction
   • Dynamic method calling

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Q5. Runtime Polymorphism (10 Marks)

A parking system calculates parking fees differently based on vehicle type.

👉 Write a Java program with the following steps:

1. Create a class Parking:
   • Method calculateFee(int hours)
   • Default behavior: return 0
2. Create subclasses:
   • TwoWheeler
   • FourWheeler
3. Override method:
   • TwoWheeler → ₹10 per hour
   • FourWheeler → ₹20 per hour
4. In the main() method:
   • Use parent class reference
   • Assign objects of both subclasses
   • Calculate and display fees
5. Output must clearly show:
   • Vehicle type
   • Hours
   • Total fee

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⭐ Bonus Question (Optional – 5 Marks)

Q6. Exception Handling with Multiple Catches

👉 Write a Java program to:

1. Take input from user:
   • Array size
   • Array elements
2. Then ask user for index to access element
3. Handle exceptions:
   • Invalid input → InputMismatchException
   • Invalid index → ArrayIndexOutOfBoundsException
4. Use:
   • Multiple catch blocks
   • finally block to print: