Wrapper's String Constructor

[Jitendra Jha]

This code is not working and i fail to understand why!!!

 public class InitDemo {

   public void display(Integer i , Integer j)
	{
		System.out.println(i);
		System.out.println(j);
	}   

    public static void main(String [] args)
    {
		InitDemo id = new InitDemo();
		id.display("20","25");
	}
}
        

I presume that java will invoke autoboxing
when i change the display method to accept one argument,it works.
please help me out or point me in the correct direction.

Thanks in advance

[Christophe Verré]

when i change the display method to accept one argument,it works.

Can you show us how you change it ?

[Pramod P Deore]

I this code when we invoke method as

  id.display("20","25");    

it will give compiler error.
But when we invoke it using

  id.display(20,25);    

it run fines. I also don't know why auto boxing is not work here. Anybody know?

[Christophe Verré]

Autoboxing helps to turn primitives into wrappers. It doesn't work with Strings.

[Jim Hoglund]

Boxing is intended to map to-and-from primitive types but String
is not a primitive. Consider this. If an int were passed to a method
that accepts only a String, boxing does not convert the int to a String.
I will convert it to an Integer type, however.

Jim ... ...

[Rob Spoor]

Jim Hoglund wrote:I will convert it to an Integer type, however.

Auto-boxing and auto-unboxing only occurs if it is necessary. If you pass an int and there is no method that takes an int,or an Integer (or broader like long, Number) the compiler will just refuse to compile the class.