code: public static String timeToString(long timeMillis) {
          DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
          return dateFormat.format(new Date(timeMillis));
      }
docs: Returns a String representation of the time.
  <p>
  This method is not particularly efficient since it generates a ton of litter.
  
  @param timeMillis time in millis
  @return the String