Understanding Constructor Overloading in Java

class Box {
    private double width;
    private double height;
    private double depth;

    // Constructor 1: All dimensions
    public Box(double width, double height, double depth) {
        this.width = width;
        this.height = height;
        this.depth = depth;
    }

    // Constructor 2: Width and height (depth defaults to 1)
    public Box(double width, double height) {
        this.width = width;
        this.height = height;
        this.depth = 1;
    }

    // Constructor 3: Width only (height and depth default to 1)
    public Box(double width) {
        this.width = width;
        this.height = 1;
        this.depth = 1;
    }

    public double getVolume() {
        return width * height * depth;
    }

    public void displayDimensions() {
        System.out.println("Width: " + width + ", Height: " + height + ", Depth: " + depth);
    }
}

public class ConstructorOverloadingExample1 {
    public static void main(String[] args) {
        Box box1 = new Box(10, 5, 2);   // Uses constructor 1
        Box box2 = new Box(8, 6);      // Uses constructor 2
        Box box3 = new Box(7);         // Uses constructor 3

        box1.displayDimensions();
        System.out.println("Volume: " + box1.getVolume());

        box2.displayDimensions();
        System.out.println("Volume: " + box2.getVolume());

        box3.displayDimensions();
        System.out.println("Volume: " + box3.getVolume());
    }
}

Width: 10.0, Height: 5.0, Depth: 2.0
Volume: 100.0
Width: 8.0, Height: 6.0, Depth: 1.0
Volume: 48.0
Width: 7.0, Height: 1.0, Depth: 1.0
Volume: 7.0

class Product {
    private String name;
    private int productId;
    private double price;

    // Constructor 1: All parameters
    public Product(String name, int productId, double price) {
        this.name = name;
        this.productId = productId;
        this.price = price;
    }

    // Constructor 2: Name and price (productId defaults to -1)
    public Product(String name, double price) {
        this.name = name;
        this.productId = -1; // Default product ID
        this.price = price;
    }

    // Constructor 3: Name and productId (price defaults to 0.0)
    public Product(String name, int productId) {
        this.name = name;
        this.productId = productId;
        this.price = 0.0;
    }

    public void displayProductInfo() {
        System.out.println("Name: " + name + ", ID: " + productId + ", Price: $" + price);
    }
}

public class ConstructorOverloadingExample2 {
    public static void main(String[] args) {
        Product product1 = new Product("Laptop", 12345, 1200.0);
        Product product2 = new Product("Mouse", 25.0);
        Product product3 = new Product("Keyboard", 67890);

        product1.displayProductInfo();
        product2.displayProductInfo();
        product3.displayProductInfo();
    }
}

Name: Laptop, ID: 12345, Price: $1200.0
Name: Mouse, ID: -1, Price: $25.0
Name: Keyboard, ID: 67890, Price: $0.0