Why do I get an error?

Question

Hello,
What I want is for a new row to be inserted each time the last column has finished being edited. I add the data in each row to a Vector() after every row. I get an ArrayIndexOutOfBoundsException when I want to insert a new row. Do you know why this happens?
Thanks
Hannah
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
import java.util.*;
public class TestGUI extends JFrame {
JTable table;
ListSelectionModel lsm;
Vector goals;
Object player = new String("");
Object minute = new String("");
boolean hasrecords;
public TestGUI() {
super("TestGUI");
goals = new Vector();
goals.addElement(new Goal("", ""));
setDefaultCloseOperation(EXIT_ON_CLOSE);
getContentPane().setLayout(new FlowLayout());
JPanel pan = new JPanel(new BorderLayout());
table = new JTable(new GoalsTableModel());
table.setCellSelectionEnabled(true);
TableColumn column;
column = table.getColumnModel().getColumn(1);
DefaultCellEditor celleditor = new DefaultCellEditor(new JTextField());
celleditor.addCellEditorListener(new TableCellEditorListener());
column.setCellEditor(celleditor);
pan.add(table.getTableHeader(), BorderLayout.NORTH);
pan.add(table, BorderLayout.CENTER);
getContentPane().add(pan);
setSize(500,500);
show();
class GoalsTableModel extends DefaultTableModel {
int numrows = 1;
public int getColumnCount() {
return 2;
public int getRowCount() {
return numrows;
public String getColumnName(int col) {
if(col==0) {
return "Player";
else {
return "Minute";
public Object getValueAt(int row, int col) {
if(!hasrecords) {
     if(col==0) {
     return player;
     else {
     return minute;
else {
Goal goalrecord = (Goal)goals.elementAt(row);
if(col==0) {
return goalrecord.player;
if(col==1) {
return goalrecord.minute;
else {
return null;
public void setValueAt(Object value, int row, int col) {
if(col==0) {
player = value;
if(col==1) {
minute = value;
public boolean isCellEditable(int row, int col) {
return true;
class Goal {
String player;
String minute;
public Goal(String player, String minute) {
this.player = player;
this.minute = minute;
class TableCellEditorListener implements CellEditorListener {
public void editingStopped(ChangeEvent e) {
goals.setElementAt(new Goal(player.toString(), minute.toString()), table.getSelectedRow());
DefaultTableModel tableModel = (DefaultTableModel)table.getModel();
     if(table.getSelectedRow() == tableModel.getRowCount() - 1) {
     String[] data = new String[] {"", ""};
     System.out.println(((Goal) goals.lastElement()).player);
     System.out.println(((Goal) goals.lastElement()).minute);
     goals.addElement(new Goal("", ""));
     GoalsTableModel goalstablemodel = (GoalsTableModel) table.getModel();
     tableModel.setRowCount(tableModel.getRowCount() + 1);
     goalstablemodel.numrows = tableModel.getRowCount() + 1;
hasrecords=true;
public void editingCanceled(ChangeEvent e) {
public static void main(String[] args) {
new TestGUI();

Answer 1

You should always indicate the line of code where the error occurs.   Also, the value of the variables in that line, as that tells you what the problem is.
There are several places where you use '+' instead of '&' with mixed types which can cause this error.
However this line:
  Dim orderid As Integer = (ds.Tables(0).Rows(0).Item(0)) + 1
is most likely the problem if you haven't checked first that there is a valid order ID returned from the query.  If the table is empty then you should initialise the ID to an arbitrary value instead of trying to calculate it.