code: public static Date addSeconds(Date date, int iSeconds) {
      Calendar dateTime = dateToCalendar(date);
      dateTime.add(Calendar.SECOND, iSeconds);
      return dateTime.getTime();
    }
docs: Adds the specified (signed) amount of seconds to the given date. For
  example, to subtract 5 seconds from the current time of the date, you can
  achieve it by calling: <code>addSeconds(Date, -5)</code>.
  
  @param date     The time.
  @param iSeconds The amount of seconds to add.
  
  @return A new date with the seconds added.