Java count all white space in String

Yesterday, before i go to sleep i tried to answer a simple question from a site. The question is about how to count all white space from String that input by a user. After a few time i failed, i found code below :

*********************************************************
COMPLETE SOURCE CODE FOR : CountAllWhitespaceInString.java
*********************************************************

::Click Here To Download This Java Source Code::

import java.util.Scanner;

public class CountAllWhitespaceInString
{
public static void main(String[]args)
{
 boolean a=true;
 Scanner sc=new Scanner(System.in);

 while(a)
 {
  System.out.println("Type EXIT to exit");
  String b=sc.nextLine();
  int whitespaceNumber=0;
 
  if(!b.equalsIgnoreCase("exit"))
  {
   try
   {
    for(int i=0;i<=b.length()-1;i++)
    {
     char temp=b.charAt(i);
     if(temp==' ')
     {
      whitespaceNumber++;
     }
    }
    System.out.println("Whitespace number is : "+whitespaceNumber);
   }
   catch(Exception exception)
   {
    System.out.println("DON'T DO THAT");
   }
  }
  else
  {
   a=false;
  }
 }
}
}

*********************************************************
JUST COMPILE AND EXECUTE IT
*********************************************************