Is this right!! Java Swing

import javax.swing.JOptionPane;

public class Addition_GUI
{
public static void main(String args[])
{
String firstInt;
String secondInt;

firstInt = JOptionPane.showInputDialog("Enter the First Integer value :");
Integer num1 = Integer.parseInt(firstInt);

secondInt = JOptionPane.showInputDialog("Enter the Second Integer value :");
Integer num2 = Integer.parseInt(secondInt);

Integer sum = num1 + num2;

String result = String.format("The sum is : %s",sum);

JOptionPane.showMessageDialog(null,result);
}
}

It didn't give any errors. But, I need a explanation. Please help me.

Quote:

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But, I need a explanation.

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About what?

Also, use the "Code tags" when posting code to the formatting is retained and the code is more readable.

Quote:

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Originally Posted by camickr

About what?

Integer sum = num1 + num2;

String result = String.format("The sum is : %s",sum);.

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Sum is declared as Integer and In second line, It pass its value to a String format specifier.

Quote:

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Originally Posted by Nifras

Sum is declared as Integer and In second line, It pass its value to a String format specifier.

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So Java automatically invokes toString().

A couple of other points:

1. You don't really need two String variables, since you're done with the first by the time you use the second. It might make your code clearer if you had just one String variable called input or something along those lines.

2. Your Integer variables can all be primitive int variables instead. Generally it's good practice to use primitives where you can, although in this case it certainly wouldn't make much difference.

-Gary-

Thanks Dude. !!!!!!!!!!!