Java Constructor – Complete Guide for Beginners

By Bhau Automation • Learn Java Constructors With Real Examples

🎯 What You Will Learn in This Java Tutorial

• What is a constructor in Java?
• Why constructors are important?
• Types of constructors in Java
• Difference between constructor and method
• Java examples and real-time use cases
• Common Java interview questions

📌 What is a Constructor in Java?

A constructor in Java is a special type of method that is automatically called when an object is created. It is used to initialize objects.

Key points:

• Constructor name must be same as class name
• It does not have any return type (not even void)
• It executes automatically when an object is created

class Student {
    String name;

    // Constructor
    Student() {
        System.out.println("Constructor is called...");
        name = "Rahul";
    }
}
  

🔧 Types of Constructors in Java

1️⃣ Default Constructor

A constructor with no parameters.

class Demo {
    Demo() {
        System.out.println("Default Constructor");
    }
}
  

2️⃣ Parameterized Constructor

Constructor with parameters to assign custom values.

class Demo {
    String name;

    Demo(String n) {
        name = n;
    }
}
  

3️⃣ Copy Constructor (Conceptual)

Java doesn’t provide a built-in copy constructor, but you can create your own.

class Demo {
    int value;

    Demo(int v) {
        value = v;
    }

    Demo(Demo obj) {
        this.value = obj.value;
    }
}
  

⚔️ Difference Between Constructor and Method in Java

🎯 Real-World Uses of Constructors

• Initializing WebDriver in Selenium
• Setting default values for objects
• Loading API configurations
• Creating model classes in Java applications

❓ Common Java Interview Questions

🎥 Watch Full Video Tutorial

👉 Watch on YouTube: Java Constructor Tutorial

🚀 Summary

• Constructors initialize objects
• They have no return type
• Methods perform actions and have return type
• Understanding constructors is essential for OOP and Java interviews

🚀 Created with ❤️ by Bhau Automation