@Override
  public void finalize() {
    if (vectorColumnMapping == null) {
      return;
    }

    Mapping mapping = vectorColumnMapping.getMapping();

    // Ordered columns are the output columns.
    sourceColumns = mapping.getValueColumns();
    outputColumns = mapping.getOrderedColumns();
    typeInfos = mapping.getTypeInfos();

    // Not needed anymore.
    vectorColumnMapping = null;
  }
This class collects column information for copying a row from one VectorizedRowBatch to
same/another batch.

In this variation, column information is ordered by the output column number.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorColumnOutputMapping.java