7.2 Real-World Banking System Architecture

src/
└── com/fincz/banking/
    ├── model/
    │   └── Account.java         (Encapsulated Bank Account with protected pin validator)
    ├── security/
    │   └── SecurityVault.java   (Private internal encryption keys)
    └── service/
        └── BankingService.java  (Public APIs for Deposit, Withdraw and Transfer)

package com.fincz.banking.model;

public class Account {
    private String accountNumber;
    private double balance;
    protected String securityPin; // केवल इनहेरिटेड या पैकेज क्लासेस के लिए

    public Account(String accNo, double initialBalance, String pin) {
        this.accountNumber = accNo;
        this.balance = initialBalance;
        this.securityPin = pin;
    }

    public String getAccountNumber() { return accountNumber; }
    public double getBalance() { return balance; }

    public boolean debit(double amount, String pin) {
        if (!this.securityPin.equals(pin)) {
            System.out.println("❌ अमान्य पिन!");
            return false;
        }
        if (amount > balance) {
            System.out.println("❌ अपर्याप्त बैलेंस!");
            return false;
        }
        this.balance -= amount;
        return true;
    }
}