🧱 What is a Constructor?

A constructor in Java is a special block of code that's called when an object is created. It’s used to initialize the object with default or user-defined values.
Syntax:
ClassName() {
// initialization code
}

It must have the same name as the class and no return type—not even void.

🎯 Why Use Constructors?

Imagine you're creating a blueprint (class) for a car. When you make a new car object, you’ll want to set the car’s brand, model, and year. That’s where constructors come in—they let you prefill those details during object creation.

🛠️ Types of Constructors in Java

Java gives you flexibility with different types of constructors.
1. Default Constructor
This is the no-argument constructor Java provides automatically if you don’t define any constructor yourself.
EXAMPLE:
class Car {
Car() {
System.out.println("Car is created");
}
}
Usage:

Car myCar = new Car(); // Output: Car is created

2. Parameterized Constructor

You define this to pass values during object creation.
example:

class Car {
    String brand;

    Car(String b) {
        brand = b;
    }
}

Usage:

Car myCar = new Car("Toyota");
System.out.println(myCar.brand); // Output: Toyota

📏 Constructor Rules to Keep in Mind

  • No return type – Not even void.
  • Must match class name exactly.
  • You can overload constructors – Create multiple versions with different parameters.
  • If you define any constructor, Java won’t give you a default one.

👀 Constructor Overloading Example
`class Car {
String brand;
int year;

Car() {
    brand = "Unknown";
    year = 0;
}

Car(String b, int y) {
    brand = b;
    year = y;
}

}

`
Usage:

`Car car1 = new Car();
Car car2 = new Car("Honda", 2022);

System.out.println(car1.brand); // Unknown
System.out.println(car2.brand); // Honda

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