private String convertTimestampToDateString(long maxTimestamp) {
     SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
     String dateString = dateFormat.format(new Date(maxTimestamp));
     return dateString;
    }

    private Long convertDateStringToTimestamp(String date) throws ParseException {
     SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date parsedDate = dateFormat.parse(date);
        return parsedDate.getTime();
    }