public static ParquetDataColumnReader getDataColumnReaderByTypeOnDictionary(
      PrimitiveType parquetType,
      TypeInfo hiveType,
      Dictionary realReader,
      boolean skipTimestampConversion,
      ZoneId writerTimezone,
      boolean legacyConversionEnabled)
      throws IOException {
    return getDataColumnReaderByTypeHelper(true, parquetType, hiveType, realReader, null,
        skipTimestampConversion, writerTimezone, legacyConversionEnabled);
  }
The reader who reads from the underlying UTF8 string.
ql/src/java/org/apache/hadoop/hive/ql/io/parquet/vector/ParquetDataColumnReaderFactory.java