Difference Encapsulation and Abstraction ?

🔐 Encapsulation — “Protect the Data”

➤ What It Is:

Encapsulation means wrapping data (variables) and methods (functions) together into a single unit, typically a class, and restricting direct access to some components using access modifiers (private, public, etc.).

🎯 Purpose:

• To hide internal object details from outside interference.
• To ensure control over data using getter and setter methods.

✅ Example:

class BankAccount {
    private double balance; // Hidden from outside

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

    public void withdraw(double amount) {
        if(amount > 0 && amount <= balance) balance -= amount;
    }

    public double getBalance() {
        return balance;
    }
}

Here, you can’t access balance directly, only via controlled methods.

🎭 Abstraction — “Show Only What’s Necessary”

➤ What It Is:

Abstraction means hiding implementation details and only exposing essential features of an object.

You can achieve abstraction in Java using:

• Abstract classes
• Interfaces

🎯 Purpose:

• To focus on what an object does, not how it does it.
• Makes code more modular, extensible, and easier to understand.

✅ Example using Interface:

interface Vehicle {
    void start();   // Abstract method
    void stop();
}

class Car implements Vehicle {
    public void start() {
        System.out.println("Car starts with key");
    }
    public void stop() {
        System.out.println("Car stops with brake");
    }
}

The user of the Vehicle interface doesn’t care how the Car starts or stops—just that it does.

🧠 Side-by-Side Comparison