More ClassCastException troubles....

Question

Hey-hey.
I have two JTables with a DataModel which extends AbstractDataModel. I have two buttons which move highlighted rows from one JTable to the other. However, when testing this I get a ClassCastException. As far as I can tell, all is correct....but I'm probably wrong. Can I have a second pair of eyes, please?
A little background info......each row in the JTable data model is actually a Vector element which in turn is an ArrayList containing three elements. So I want to return each ArrayList object and add it to the other JTable. I'm using the List interface to cover all my bases in regards to parameters and returns, but when I click my "move" button, I get a ClassCastException which is here: -
Exception occurred during event dispatching:
java.lang.ClassCastException
at ExcludeListFrame.actionPerformed(ExcludeListFrame.java:153)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)
at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)
<snipped here - I'm pretty sure stuff below this isn't important to us mere mortals>
Anyway, here is my DataModel code...
import javax.swing.table.AbstractTableModel;
import java.util.Collection;
import java.util.ArrayList;
import java.util.Vector;
import java.util.Map;
import java.util.List;
import java.util.Iterator;
import java.util.Set;
import commonfiles.Utility;
public class ListDataModel extends AbstractTableModel implements Cloneable {
    private final int NUM_COLUMNS = 3;
    private Vector theRowData;
    private String[] columnNames = {"USER_REFNO", "CODE", "USER_NAME"};
    // Constructor : Create empty data model.
    public ListDataModel() {
        theRowData = new Vector();
    // Constructor : Create data model from another collection.
    public ListDataModel(Collection someCollection) {
        theRowData = new Vector();
        theRowData.addAll(someCollection);
    public ListDataModel(ArrayList arrayCollection) {
        ArrayList theColumnArray;
        Map rowMap;
        theRowData = new Vector();
        for (int i = 0; i < arrayCollection.size(); i++) {
            rowMap = (Map)arrayCollection.get(i);
            theColumnArray = new ArrayList();
            theColumnArray.add((Object)rowMap.get(columnNames[0]));
            theColumnArray.add((Object)rowMap.get(columnNames[1]));
            theColumnArray.add((Object)rowMap.get(columnNames[2]));
            theRowData.add(theColumnArray);
    public Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException cnse) {
            throw new RuntimeException(cnse.toString());
    public Object getValueAt(int rowIndex, int columnIndex) {
        ArrayList theColumnArray;
        theColumnArray = (ArrayList)theRowData.get(rowIndex);
        return(Object)theColumnArray.get(columnIndex);
    public List getRowAt(int rowIndex) {
        return (List)theRowData.get(rowIndex);
    public void removeRowAt(int rowIndex) {
        theRowData.removeElementAt(rowIndex);
    public void addRow(List rowObject) {
        theRowData.addElement((ArrayList)rowObject);
    // Check to see if a particular Table cell is editable.
    // In this model, none of the cells are directly editable.
    public boolean isCellEditable(int rowIndex, int columnIndex) {
        return false;
    public int getColumnCount() {
        return columnNames.length;
    // Return the column headers.
    public String[] returnColumnNames() {
        return columnNames;
    // Return the name of a specific column.
    public String getColumnName(int col) {
        return columnNames[col].toString();
    public int getRowCount() {
        return theRowData.size();
    public Vector returnAllData() {
        return theRowData;
}...and here is the code that fails.....
        int[] selectedRows;
        List listItem;
        // Event that happens when the List Add (>>) button is pressed.
        if (e.getSource() == btnListAdd) {
            // Get the number of selected (hightlighted) rows.
            selectedRows = this.tableUserList.getSelectedRows();
            if (selectedRows.length > 0) {
                for (int row = 0; row < selectedRows.length; row++) {
                    listItem = (List)((ListDataModel)tableUserList.getModel()).getRowAt(row);
                    ((ListDataModel)tableExcludeList.getModel()).addRow((List)listItem);    //    <----- ClassCastException thrown here.   
                tableExcludeList.repaint();
        }I'm sure this is obvious, but I'm starting to go cross-eyed over this. Thanks for any help. I'm pretty sure I'm casting things where I should and that List interfaces are a blanket type for certain Collections as parameters, so I don't really know what I'm doing wrong.

Answer 1

I've done a little further research. I first thought to check that the item I returned was something that implemented the List interface, as if it didn;t this could cause it to fail. So I put in the line.
System.out.println(listItem.getClass().toString());To which I get back: - class java.util.ArrayList
So, its not that. I just don't see why adding this object to the Vector would fail. This method is almost too simple to fall over and the Exception happens within the actionPerformed method.