title: DecimalFormat pattern problem
body: <p>I try to format a number using NumberFormatter in Android. I use the code bellow and it works perfectly:</p>
  
  <pre><code> NumberFormat formatter = new DecimalFormat("###,###");
   String myFormattedString = formatter.format(123456);
  </code></pre>
  
  <p>But, when i use a pattern with space, like that: <code>new DecimalFormat("###,# ##");</code> it throws an <code>IllegalArgumentException</code>. I've read documentation about NumberFormatter and DecimalFormatter and found nothing about spaces in patterns. Can anyone explane me why can't i use spaces or how to add them as allowed characters. 
   Thanks in advance!!!</p>