presto-accumulo/src/main/java/io/prestosql/plugin/accumulo/model/RowSchema.java/RowSchema/getColumn
class RowSchema:    public AccumuloColumnHandle getColumn(int i)
    {
        checkArgument(i >= 0 && i < columns.size(), "column index must be non-negative and less than length");
        return columns.get(i);
    }