title: comma separator in a string variable
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/3672731/how-can-i-format-a-string-number-to-have-commas-and-round">How can I format a String number to have commas and round?</a>  </p>
  </blockquote>
  
  
  
  <p>I have a string variable (That is a number in string format) and now I want to use a comma for separation for every three digits. how can I do it?
  My technology is Struts2</p>