---
title: "Encapsulation"
description: Data hiding, access modifiers, getter/setter methods, and static members in Java.
---
## Definition

Encapsulation is the practice of bundling data (fields) and the methods that operate on that data into a single class, while restricting direct access to the internal state.

## Access Modifiers

| Modifier    | Class | Package | Subclass | World |
| ----------- | ----- | ------- | -------- | ----- |
| `public`    | Yes   | Yes     | Yes      | Yes   |
| `protected` | Yes   | Yes     | Yes      | No    |
| _default_   | Yes   | Yes     | No       | No    |
| `private`   | Yes   | No      | No       | No    |

## Getter and Setter Methods

- **Getters** return the value of a private field.
- **Setters** assign a value to a private field, optionally with validation.

## Static Variables and Methods

- **`static` variables** — Shared across all instances of a class.
- **`static` methods** — Belong to the class rather than any instance. Called via `ClassName.method()`.

## Example

```java
// EncapsulationDemo.java
// Demonstrates encapsulation using private variables and getter/setter methods.

class Person {
	// Private variables (data hiding)
	private String name;
	private int age;

	// Getter for name
	public String getName() {
		return name;
	}

	// Setter for name
	public void setName(String n) {
		name = n;
	}

	// Getter for age
	public int getAge() {
		return age;
	}

	// Setter for age
	public void setAge(int a) {
		age = a;
	}
}

public class EncapsulationDemo {
	public static void main(String[] args) {
		// Create Person object and set values
		Person p = new Person();
		p.setName("Bob");
		p.setAge(25);
		// Print details
		System.out.println(p.getName() + " is " + p.getAge() + " years old.");
	}
}
```

> Full source: [`examples/06-encapsulation/EncapsulationDemo.java`](https://github.com/University-Of-Sri-Jayewardenepura/Java/blob/main/examples/06-encapsulation/EncapsulationDemo.java)