What is POJO and why we use POJO?

🤔 What is a POJO in Java?

POJO stands for Plain Old Java Object.
It means a simple Java class that:

• Only has variables (fields) to store data
• Has getter and setter methods to access that data
• Doesn’t extend any framework classes (like HttpServlet, etc.)
• Doesn’t implement any special interfaces (unless needed)
• Has no special rules or annotations

In short: a POJO is just a clean, lightweight class for holding data.

📦 Simple Example of POJO

public class Employee {
    private int id;
    private String name;

    // Constructor
    public Employee(int id, String name) {
        this.id = id;
        this.name = name;
    }

    // Getters
    public int getId() { return id; }
    public String getName() { return name; }

    // Setters
    public void setId(int id) { this.id = id; }
    public void setName(String name) { this.name = name; }
}

🎯 Why Do We Use POJOs?

• To store and transfer data (like in APIs, databases, etc.)
• To keep classes clean and free from unnecessary logic
• Easy to test, easy to read
• Used in frameworks like Spring and Hibernate

✅ Interview Key Points