private static List<ColStatistics> convertColStats(List<ColumnStatisticsObj> colStats) {
    if (colStats == null) {
      return Collections.emptyList();
    }
    List<ColStatistics> stats = new ArrayList<>(colStats.size());
    for (ColumnStatisticsObj statObj : colStats) {
      ColStatistics cs = getColStatistics(statObj, statObj.getColName());
      if (cs != null) {
        stats.add(cs);
      }
    }
    return stats;
  }
Get table level column statistics for needed columns
@param table
         - table
@param neededColumns
         - list of needed columns
@return column statistics
ql/src/java/org/apache/hadoop/hive/ql/stats/StatsUtils.java