public static ZoneId getWriterTimeZoneId(Map<String, String> metadata) {
    if (metadata == null) {
      return null;
    }
    String value = metadata.get(DataWritableWriteSupport.WRITER_TIMEZONE);
    try {
      if (value != null) {
        return ZoneId.of(value);
      }
    } catch (DateTimeException e) {
      throw new RuntimeException("Can't parse writer time zone stored in file metadata", e);
    }

    return null;
  }
Get a valid zoneId from some metadata, otherwise return null.
ql/src/java/org/apache/hadoop/hive/ql/io/parquet/read/DataWritableReadSupport.java