code: public static TimeZone timeZoneForName(String tzString) {
          // This is a horrible hack since there is no easier way to get a timezone
          // only if the string is recognized as a timezone.
          // The TimeZone.getTimeZone javadoc says the following:
          //   Returns:
          //       the specified TimeZone, or the GMT zone if the given ID cannot be
          //       understood.
          TimeZone tz = TimeZone.getTimeZone(tzString);
          if (tz.hasSameRules(BOGUS_TIMEZONE)) {
              // see if the user really was asking for GMT because if
              // TimeZone.getTimeZone can't recognize tzString, then that is what it
              // will return.
              Matcher m = UTC_TZID.matcher(tzString);
              if (m.matches()) {
                  return TimeUtils.utcTimezone();
              }
              // unrecognizable timezone
              return null;
          }
          return tz;
      }
docs: returns the timezone with the given name or null if no such timezone.
  calendar/common/ICalUtil uses this function