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L1.3 — Encapsulation & Constructors introduces the first core principle of OOP: encapsulation, covering how to protect data using access modifiers, implement getters/setters for controlled access, and create constructors to properly initialize objects.

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📋 At a Glance

• [ ] Review the difference between public and private access modifiers
• [ ] Practice writing getter and setter methods with validation
• [ ] Understand when and why to use the this keyword
• [ ] Master constructor syntax and overloading rules
• [ ] Remember the default constructor behavior
• [ ] Apply the "always start with private" principle
• [ ] Practice creating objects with different constructor signatures
• [ ] Understand the benefits of encapsulation for code maintenance

1. What is Encapsulation?

Encapsulation is one of the three core principles of Object-Oriented Programming. It involves:

1. Bundling data with methods - Combining related data (properties) and the methods that operate on that data into a single class
2. Controlling access - Preventing direct access to internal data from external classes
3. Providing clean interfaces - Offering controlled ways to interact with the object through public methods

The Problem Without Encapsulation

Consider this simple Person class:

public class Person {
    public String name;
    public int age;
    
    public void tell() {
        System.out.println("Name: " + name + ", Age: " + age);
    }
}