Explanation about loosely coupled and tightly coupled?

🔗 What Is Coupling?

Coupling means how strongly one class is connected to another class in your program.

🔴 Tightly Coupled

• One class is directly dependent on another.
• If you change one class, the other may break.
• Think of it like two people walking with their shoelaces tied together—one trip and both fall.

👀 Simple Example:

class Engine {
    void start() {
        System.out.println("Engine started");
    }
}

class Car {
    Engine engine = new Engine(); // tightly connected

    void drive() {
        engine.start();
    }
}

In this example, the Car class knows exactly which Engine it needs. You can’t easily swap the engine.

🟢 Loosely Coupled

• One class depends on what the other class can do, not how it does it.
• Classes are connected using interfaces, not specific classes.
• It’s like using a charger that works with any phone—as long as it supports the same plug.

👀 Simple Example:

interface Engine {
    void start();
}

class PetrolEngine implements Engine {
    public void start() {
        System.out.println("Petrol engine started");
    }
}

class Car {
    Engine engine;

    Car(Engine engine) {
        this.engine = engine;
    }

    void drive() {
        engine.start();
    }
}

Now you can use any kind of engine—just pass it to the Car when you create it.

🧠 Why This Matters (Short & Sweet)