🔒 Encapsulation in Java – Data Security Made Simple

When we talk about OOP in Java, one of the most powerful principles is Encapsulation. Think of it as putting sensitive data inside a box and only opening it with a proper key (methods).

🌟 What is Encapsulation?

👉 Encapsulation is the process of hiding data (variables) inside a class and providing controlled access using methods (getters & setters).
It prevents direct access to data and protects it from unwanted modification.

🏦 Real-World Analogy

• Imagine your ATM card & PIN.

  • Your bank balance (data) is hidden.

  • You can’t directly take money out from the vault.

  • You use an ATM machine (methods) to access your balance safely.

That’s Encapsulation in action!

⚡ Key Points of Encapsulation

• ✅ Class variables are kept private.

• ✅ Public methods (getters & setters) are used to access or modify data.

• ✅ Provides data security.

• ✅ Increases code maintainability & flexibility.

🖥️ Java Example: Encapsulation in Action

class BankAccount {
    // Private data
    private String accountHolder;
    private double balance;

    // Getter method
    public String getAccountHolder() {
        return accountHolder;
    }

    // Setter method
    public void setAccountHolder(String name) {
        this.accountHolder = name;
    }

    // Getter method
    public double getBalance() {
        return balance;
    }

    // Setter method
    public void deposit(double amount) {
        if (amount > 0) {
            balance += amount;
        }
    }
}

public class Main {
    public static void main(String[] args) {
        BankAccount acc = new BankAccount();
        acc.setAccountHolder("Ravi");
        acc.deposit(5000);

        System.out.println("Account Holder: " + acc.getAccountHolder());
        System.out.println("Balance: " + acc.getBalance());
    }
}

✅ Output:

Account Holder: Ravi  
Balance: 5000.0  

🎯 Benefits of Encapsulation

• 🔐 Security → Data is safe from unauthorized access.

• 🛠 Flexibility → Easy to change the code later without breaking other parts.

• 📦 Reusability → Encapsulated classes can be reused across projects.

• 🚀 Maintainability → Changes in one part don’t affect the whole program.

✨ Quick Summary

👉 Encapsulation = Data + Methods bundled together in a class with restricted access.
It ensures security, control, and clean code architecture.

💡 Pro Tip: Always make your variables private and provide public getter/setter methods when needed.