Class and Object in Java

A class is a blueprint that defines fields (data) and methods (behaviour). An object is an instance of a class: a real entity created in memory with new.

AnalogyClass = the design of a car. Objects = the actual cars built from that design.

One class (blueprint) — many objects (instances)

Java

class Car {
    String color, model;
    int speed;

    void run() {
        System.out.println(color + " " + model + " running at " + speed + " km/h");
    }
}

public class Main {
    public static void main(String[] args) {
        Car c1 = new Car();
        c1.color = "Red"; c1.model = "Swift"; c1.speed = 80;

        Car c2 = new Car();
        c2.color = "Blue"; c2.model = "City"; c2.speed = 60;

        c1.run();
        c2.run();
    }
}

Red Swift running at 80 km/h Blue City running at 60 km/h

Ways to Create an Object

Using new (most common)
Using clone()
Using reflection (newInstance())
Using deserialization

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