Matching rules between from / to schema -revisted ( Use the avro model)

  protected void tryFillNullInArrayForUnexpectedColumn(Column column,
      Object[] array, int index) throws SqoopException {
    if (!column.isNullable()) {
      throw new SqoopException(SchemaError.SCHEMA_0004, "Target column " +
          column + " didn't match with any source column and cannot be null.");
    }

    LOG.warn("Column " + column +
        " has no matching source column. Will be ignored.");
    array[index] = null;
  }