code: public static String getUTCTimeOrEmpty(final Date value) {
          if (value == null) {
              return Constants.EMPTY_STRING;
          }
  
          final DateFormat iso8601Format = new SimpleDateFormat(ISO8601_PATTERN, LOCALE_US);
          iso8601Format.setTimeZone(UTC_ZONE);
  
          return iso8601Format.format(value);
      }
docs: Returns the UTC date/time for the specified value using the ISO8601 pattern.
  
  @param value
  A <code>Date</code> object that represents the date to convert to UTC date/time in the ISO8601
  pattern. If this value is <code>null</code>, this method returns an empty string.
  
  @return A <code>String</code> that represents the UTC date/time for the specified value using the ISO8601
  pattern, or an empty string if <code>value</code> is <code>null</code>.