When is toString() method called

I got an example to override the toString() method.

import java.util.Scanner; 

public class Demo{ 

    String name = "";
    String age = "";

    Demo(String name, String age){
            this.name = name;
            this.age = age;
        }


    public static void main(String[] args) {  
        Scanner scanner = new Scanner(System.in);  

        System.out.print("Enter the name:");  
        String name = scanner.next();  
        System.out.print("Enter the age:");  
        String age = scanner.next();  

        Demo test = new Demo(name, age);  
        System.out.println(test);  

    }  

    public String toString() {  
        return ("Name=>" + name + " and " + "Age=>" + age);  
    }  
}

My doubt is, how is it printing test as Name=>abc and Age=>12 even when toString() method is not being called neither from constructor nor from main?

Jon Skeet
people
quotationmark

You're calling System.out.println(test), which is a call to PrintStream.println(Object). That will call toString() on the reference you pass in, via String.valueOf:

Prints an Object and then terminate the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokes print(String) and then println().

people

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