code: public static long convertAlldayUtcToLocal(Time recycle, long utcTime, String tz) {
          if (recycle == null) {
              recycle = new Time();
          }
          recycle.timezone = Time.TIMEZONE_UTC;
          recycle.set(utcTime);
          recycle.timezone = tz;
          return recycle.normalize(true);
      }
docs: Convert given UTC time into current local time. This assumes it is for an
  allday event and will adjust the time to be on a midnight boundary.
  
  @param recycle Time object to recycle, otherwise null.
  @param utcTime Time to convert, in UTC.
  @param tz      The time zone to convert this time to.