code: public static ZoneId toZoneId(TimeZone tz) {
          // Android-changed: don't support "old mapping"
          return ZoneId.of(tz.getID(), ZoneId.SHORT_IDS);
      }
docs: J2ObjC: moved from java.util to keep jre_core independent of jre_time.
  Converts a {@code TimeZone} object to a {@code ZoneId}.
  
  @return a {@code ZoneId} representing the same time zone as this
  {@code TimeZone}
  @since 1.8