Tight Coupling vs Loose Coupling in Java (with Examples)

Learn the difference between tight coupling and loose coupling in Java. Understand how loose coupling improves flexibility, testability, and design with simple examples.

This is a member-only article. For non-members, read this article for free on my blog: Tight Coupling vs Loose Coupling in Java.

🔍 What is Coupling in Java?

Coupling refers to the degree of dependency between two classes or modules.

• 🤝 Tight Coupling = Classes are strongly dependent on each other.
• 🪢 Loose Coupling = Classes are independent and interact via abstraction.

🚨 Tight Coupling (Bad Design Practice)

A tightly coupled class knows too much about another class. Changes in one class can break the other.

🔧 Example: Tight Coupling

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

class Car {
    Engine engine = new Engine(); // Direct dependency

    public void drive() {
        engine.start();
        System.out.println("Car is driving");
    }
}

❌ Problems:

• You can’t switch to another engine easily (e.g., ElectricEngine).