public E get(int rowIndex, int columnIndex) {
        if (_initialized) {
            return _columnList.get(columnIndex).get(rowIndex);
        } else {
            checkRowIndex(rowIndex);
            checkColumnIndex(columnIndex);

            return null;
        }
    }
public E get ( int rowIndex , int columnIndex ) { if ( _initialized ) { return _columnList . get ( columnIndex ) . get ( rowIndex ) ; } else { checkRowIndex ( rowIndex ) ; checkColumnIndex ( columnIndex ) ; return null ; } }
@param rowIndex
@param columnIndex
@return