Comma separated lists in java

I find myself doing this for a user a million times and have taken until now to take care of the formatting somewhere else. If you need a list that has commas in between items, but of course doesn't have a trailing comma, something like this is handy:

 /**
  * bch: formats a comma-separated list
  * @param items string separated by spaces
  * @return list in format a, b, c
  */
 public static String commalist(String items) {
  StringTokenizer st = new StringTokenizer(items);
  StringBuffer sb = new StringBuffer();
  while (st.hasMoreElements()) {
   sb.append(st.nextToken());
     if (st.hasMoreElements()) {
    sb.append(", ");
   }
  }
  return sb.toString();
 }