Constructor in Java and Overloaded Constructor Example Program

Constructor in Java – Explained with Examples

A constructor in Java is a special method used to initialize objects. It shares the same name as the class and has no return type. This tutorial explains the basics of constructors and covers constructor overloading in Java with real examples.

Watch: Java Constructor & Constructor Overloading (YouTube)

What is a Constructor?

A constructor is automatically called when an object is created.
It has the same name as the class.
It does not have a return type (not even void).

Example: Product Class

class Product {
    int id;
    String title;
    double price;

    // Default Constructor
    Product() {
        System.out.println("Default constructor called");
    }

    // Parameterized Constructor
    Product(int id, String title, double price) {
        this.id = id;
        this.title = title;
        this.price = price;
    }
}

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class Product {

int id;

String title;

double price;

// Default Constructor

Product() {

System.out.println("Default constructor called");

}

// Parameterized Constructor

Product(int id, String title, double price) {

this.id = id;

this.title = title;

this.price = price;

}

}

In the above example this.id refers to the instance variable while only id refers to the parameter in the constructor

Constructor Overloading

Constructor overloading means creating multiple constructors in the same class with different parameter lists. This allows you to create objects in different ways.

Constructor vs Method in Java

Constructor	Method
Same name as class	Can have any name
No return type	Must have a return type
Called automatically	Called explicitly
Used to initialize object	Used to perform actions

Summary

Java supports constructor overloading via different parameter types/count.
No return type — not even void.
Used to initialize objects with or without parameters.

Interview Tip:

Overloading is always based on parameters, not return type.

Java does not allow two constructors with the same parameter list even if the return type is different.
Be prepared to explain the flow of constructor invocation.

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