if (row<0 || row > data.size()) {
if (row<0 || row > _data.size()) {
        public synchronized Object getValueAt(int row, int column) {            if (row<0 || row > data.size()) {                throw new ArrayIndexOutOfBoundsException("Attempt to get row " + row + ", column " + column + " : row does not exist!");            }            String[] rowdata = (String[]) data.get(row);            if (column <= columnNames.length) {                return rowdata[column];            } else {                throw new ArrayIndexOutOfBoundsException("Attempt to get row " + row + ", column " + column + " : column does not exist!");            }        }