Constructor Method and Constructor Overloading in Java

Features of a Constructor

🔹 Automatically called when an object is created.

🔹 Has the same name as the class.(Instead of giving another name java consider it method and ask a return type)

🔹 Does not have a return type.

🔹 Used to initialize object specific values.

Types of Constructors

1. Default Constructor (Implicit)

🔹 If you do not write any constructor in your class, the Java compiler automatically inserts a blank, no-argument constructor during compilation.

🔹 This constructor keeps by Java virtual Machine.

2.No-Argument Constructor (Explicit)

🔹 A constructor written by the programmer with no parameters.

🔹 This constructor is created by user.

public MobilePhone(){
System.out.println("No arguments Constructor");
}

3.Parameterized Constructor

🔹 A constructor that accepts parameters to initialize objects with specific values.

public  MobilePhone(String name,int price,int battery){
this.name = name;
this.price = price;
this.battery = battery;
}

Constructor Overloading

🔹 Constructor overloading is the process of defining two or more constructors in the same class with different parameter lists.

🔹 The compiler decides which constructor to call, based on the number or type of arguments passed when creating an object.

public  MobilePhone(String name,int battery){
this.name = name;
this.battery = battery;
}

Code example

public class MobilePhone
{
String name;
int price;
int battery;

public MobilePhone(){
System.out.println("No arguments Constructor");
}

public  MobilePhone(String name,int price,int battery){
this.name = name;
this.price = price;
this.battery = battery;
}

public  MobilePhone(String name,int battery){
this.name = name;
this.battery = battery;
}

public static void main(String[] args)
{
   // No argument constructor
   MobilePhone brand = new MobilePhone();

   //Parameterized Constructor
   MobilePhone brand1 = new MobilePhone("Samsung s25 ultra",120000,5000);
   MobilePhone brand2 = new MobilePhone("Realmep4 power",28000,10000);

   //Constructor overloading(Two parameters)
   MobilePhone brand3 = new MobilePhone("Vivo t5x",7200);

   System.out.println("BrandName :" + brand1.name);
   System.out.println("Price :" + brand1.price);
   System.out.println("BrandName :" + brand2.name);
   System.out.println("Price :" + brand2.price);
   System.out.println("Battery :" + brand2.battery);
   System.out.println("BrandName :" + brand3.name);
   System.out.println("Battery :" + brand3.battery);
}
}

Output