DecimalFormat Class (Question on what the # does)

Here is my code:

Code:

---

import java.text.DecimalFormat;

import java.util.Scanner;

public class decform_checker
{
        public static void main (String [] args)
        {
                Scanner kb = new Scanner(System.in);
               
                double number = kb.nextDouble();
               
                DecimalFormat formatter = new DecimalFormat("#0,000.000%");
                System.out.println(formatter.format(number));
        }
}

---

I would appreciate it if somebody could explain what the # does in detail because I don't understand what I read on it and I don't find much to read about it either.

Thanks in advance!

take a look Special Pattern Characters...

DecimalFormat