Encapsulation in Java

In this lesson: Hide data with private fields and public getters/setters in Java — benefits and examples with output. In Hindi & English.

What is Encapsulation?

Encapsulation means wrapping the data (variables) and the code (methods) that work on that data into a single unit — a class — and hiding the internal details from the outside world. In Java it is achieved by making fields private and giving controlled access through public getter and setter methods.

How to Achieve Encapsulation

• Declare the class fields as private.
• Provide public getter methods to read them.
• Provide public setter methods to change them (with validation).

class Account {
    private double balance;   // hidden data

    public double getBalance() {   // getter
        return balance;
    }
    public void deposit(double amt) {  // controlled setter
        if (amt > 0) balance += amt;   // validation!
    }
}
public class Main {
    public static void main(String[] a) {
        Account ac = new Account();
        ac.deposit(500);
        System.out.println(ac.getBalance());
    }
}

500.0

Benefits of Encapsulation

Summary

• Encapsulation = data + methods in one class, with internal details hidden.
• Achieved by private fields + public getters/setters.
• Gives data hiding, validation, flexibility and controlled access.