code: public static long changeTimestampToLong(String dateFormat,
              String timestamp, String zoneId) {
          return changeTimestampToLong(getSimpleDateFormat(dateFormat, zoneId),
                  timestamp);
      }
docs: Change timestamp to long long.
  
  @param dateFormat the date format
  @param timestamp  the timestamp
  @param zoneId     the zone id
  @return the long