---
title: "Constructor in java"  
description: "The constructor in Java is a special type of method that is used to initialize the object. Java constructor is invoked at the time of object creation"  
author: "ANkita gupta"  
published: 2015-06-01  
updated: 2018-02-24  
canonical: https://www.mindstick.com/blog/10904/constructor-in-java  
category: "java"  
tags: ["java"]  
reading_time: 2 minutes  

---

# Constructor in java

The constructor in [Java](https://www.mindstick.com/articles/12214/web-development-company-in-india-laid-on-the-foundation-of-concrete-java-programming) is a special type of [method](https://www.mindstick.com/forum/166/webservice-method) that is used to initialize the object.

Java constructor is invoked at the time of object creation.It constructs the [value](https://www.mindstick.com/articles/23219/an-optimized-description-adds-value-to-experience-and-in-turn-effectively-guest-posting-packages) i.e. provides data for the object that is why it is [known as](https://answers.mindstick.com/qa/35703/ricky-ponting-is-also-known-as-what) the constructor.

\

## [Rules](https://www.mindstick.com/articles/43901/blackjack-rules) for creating java constructor:

- Constructor name must be same as its [class name](https://www.mindstick.com/forum/12871/how-to-get-class-name).
- The constructor must have no [explicit](https://www.mindstick.com/interview/2677/can-you-explain-about-implicit-and-explicit-type-casting) return type.

## There are two types of constructors:

1. [Default constructor](https://www.mindstick.com/forum/34531/default-constructor) (no-arg constructor)
2. Parameterized constructor

![Constructor in java](https://www.mindstick.com/blogs/4b929ddb-642a-47e8-a50a-de4b544826aa/images/02e544e8-b6b0-469a-a286-d1cad85a0024.png)

Constructor that have no parameter is known as default parameter.

```
<class_name>(){}
```

e.g. of the default constructor, we are creating the no-arg constructor in the Bike class. It will be invoked at the time of object creation.

```
class Bike1{
Bike1(){System.out.println("Bike is created");}
public static void main(String args[]){
Bike1 b=new Bike1();
}
}
```

## Output:

Bike is created.

\

A constructor that have parameter is known as a parameterized constructor.

example, we have created the constructor of Student class that have two parameters. We can have any number of parameters in the constructor.

```
class Student4{
    int id;
    String name;

    Student4(int i,String n){
    id = i;
    name = n;
    }
    void display(){System.out.println(id+" "+name);}

    public static void main(String args[]){
    Student4 s1 = new Student4(111,"Karan");
    Student4 s2 = new Student4(222,"Aryan");
    s1.display();
    s2.display();
   }
}
```

## Output:

111 Karan

222 Aryan

---

Original Source: https://www.mindstick.com/blog/10904/constructor-in-java

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