⏱️ Time: 2 Hours
📊 Maximum Marks: 50

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📌 Instructions (Read Carefully):

• Attempt all questions.
• Each question must be written in a separate class/file.
• Follow proper OOP concepts and structure.
• Use Scanner class wherever input is required.
• Output must be clearly formatted and labeled.
• Add comments to explain important logic.

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🔹 Section A – Core Programming (30 Marks)

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Q1. Class, Object, Constructor & Method Logic (10 Marks)

📘 Scenario: Electricity Usage Tracker

An electricity department wants to track usage and calculate monthly bill.

👉 Write a Java program with the following requirements:

1. Create a class named ElectricityUsage.
2. Declare the following instance variables:
   • consumerId (int)
   • consumerName (String)
   • unitsConsumed (int)
3. Create a parameterized constructor:
   • Initialize all variables using this keyword
4. Create a method calculateBill():
   • If units ≤ 100 → ₹2 per unit
   • If units ≤ 300 → ₹4 per unit
   • If units > 300 → ₹6 per unit
5. Create a method displayDetails():
   • Display consumer details
   • Display calculated bill
6. In the main() method:
   • Take input for one consumer
   • Create object
   • Display details

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Q2. Inheritance + Overriding with Extra Logic (10 Marks)

📘 Scenario: Online Course Pricing

Different courses have different pricing rules.

👉 Write a Java program as follows:

1. Create base class Course:
   • Method calculateFee(int duration)
   • Default message: Fee calculation not defined
2. Create subclasses:
   • ProgrammingCourse
   • DesignCourse
3. Override method:
   • ProgrammingCourse:
     • Fee = duration × ₹100
     • If duration > 30 → apply 10% discount
   • DesignCourse:
     • Fee = duration × ₹80
4. In the main() method:
   • Take duration as input
   • Create objects of both subclasses
   • Display calculated fee
5. Output must clearly show:
   • Course type
   • Duration
   • Final fee

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Q3. Encapsulation with Business Logic (10 Marks)

📘 Scenario: Mobile Recharge System

A telecom company manages user balance securely.

👉 Write a Java program with the following steps:

1. Create a class RechargeAccount.
2. Declare private variables:
   • mobileNumber (String)
   • userName (String)
   • balance (double)
3. Provide:
   • Getter and Setter methods
4. Add validation:
   • Balance cannot be negative
5. Create methods:
   • recharge(double amount) → add balance
   • makeCall(int minutes):
     • Deduct ₹1 per minute
     • If insufficient balance → display "Low balance"
6. In the main() method:
   • Create object
   • Perform recharge
   • Simulate call
   • Display final balance

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🔹 Section B – Advanced OOP Concepts (20 Marks)

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Q4. Abstract Class with Multiple Methods (10 Marks)

📘 Scenario: Report Generation System

Different report types generate output differently.

👉 Write a Java program as follows:

1. Create an abstract classReport:
   • Abstract method generateReport()
   • Concrete method printHeader() → prints "Report Generated"
2. Create subclasses:
   • SalesReport
   • StudentReport
3. Implement abstract method:
   • SalesReport → "Generating Sales Report"
   • StudentReport → "Generating Student Report"
4. In the main() method:
   • Use abstract class reference
   • Call both methods (printHeader() and generateReport())

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Q5. Runtime Polymorphism with Return Values (10 Marks)

📘 Scenario: Tax Calculation System

Different income types have different tax rules.

👉 Write a Java program with the following steps:

1. Create a class Tax:
   • Method calculateTax(double income)
   • Default: return 0
2. Create subclasses:
   • SalariedTax
   • BusinessTax
3. Override method:
   • Salaried → 10% of income
   • Business → 20% of income
4. In the main() method:
   • Take income as input
   • Use parent class reference
   • Assign subclass objects
   • Display tax for both
5. Output must clearly show:
   • Income type
   • Tax calculated

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⭐ Bonus Question (Optional – 5 Marks)

Q6. Exception Handling + Custom Validation

📘 Scenario: Password Validation System

👉 Write a Java program to:

1. Ask user to enter password
2. Validate:
   • Length must be at least 6 characters
3. If invalid:
   • Throw exception with message "Weak Password"
4. Use:
   • try-catch
   • throw keyword
5. Finally block should print: