NBKRIST Java Hub

Problem Statement: Bank Loan System

Your task is to create a simple Bank Loan system using core Java concepts. This problem will help you understand how to use **interfaces**, **inheritance**, and **packages** to structure a well-organized application.

Functional Requirements

• Loan Types: The system must handle at least two types of loans, such as a **Home Loan** and a **Car Loan**.
• Monthly Interest: Every loan must be able to calculate its monthly interest payment based on its amount, rate, and term.

Technical Requirements

• 1. Use Packages:
  • Organize your code into two packages: com.nbkrist.loans.model for your class definitions and com.nbkrist.loans.main for your main application logic.
• 2. Create an Interface:
  • In the com.nbkrist.loans.model package, create an interface named LoanCalculations with a single method: double calculateMonthlyInterest().
• 3. Create a Base Class:
  • In the same package, create an **abstract** class named Loan that **implements** the LoanCalculations interface.
  • The Loan class should have fields for loanAmount, interestRate, and loanTerm.
  • The calculateMonthlyInterest() method in this class must be **abstract**.
• 4. Create Concrete Classes (Inheritance):
  • Create two classes, HomeLoan and CarLoan, that both **extend** the `Loan` abstract class.
  • Each class must provide its own specific implementation for the `calculateMonthlyInterest()` method.
• 5. Demonstrate in `Main`:
  • In the `com.nbkrist.loans.main` package, create a class with a `main` method.
  • You will need to use the `import` statement to access the loan classes from the other package.
  • Create a `HomeLoan` object and a `CarLoan` object.

Testing Requirements

Your main method must demonstrate the program works by testing the following scenarios:

1. Individual Loan Test:
   • Create a HomeLoan object (e.g., loan amount 500000, rate 0.05, term 360). Print its calculated monthly interest.
   • Create a CarLoan object (e.g., loan amount 30000, rate 0.08, term 60). Print its calculated monthly interest.
2. Polymorphism & Package Test:
   • Create a List of type Loan. Add both the `HomeLoan` and `CarLoan` objects to it.
   • Loop through the list and call the `calculateMonthlyInterest()` method on each object. The output should show the correct calculation for each loan type, demonstrating how packages and polymorphism work together.