Problem: JTable - Zeile anhängen

import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.DefaultTableModel;

class ProductTable {
	private JTable table = null;
	private MyTableModel tmodel = null;
	
	public void createProductTable() {
    	    JPanel panel = new JPanel(new GridLayout(2,1));
    	    JPanel buttonPanel = new JPanel(new FlowLayout());
    	
    	    tmodel = new MyTableModel();
    	    table = new JTable(tmodel.data, tmodel.columnNames);
    	    JScrollPane sp = new JScrollPane(table);
    	
    	    JButton b_newDataset = new JButton("neuer Datensatz");
            b_newDataset.addActionListener(new ButtonListener());
        
            buttonPanel.add(b_newDataset);
        
            panel.add(sp);
            panel.add(buttonPanel);
        
            App.contentPanel.removeAll();
            App.contentPanel.add(panel);
            App.contentPanel.setVisible(true);
        }
    
	
	class MyTableModel extends DefaultTableModel {
		private Object[][] data = null; 
		private String[] columnNames = null;
		
		public MyTableModel() {
			data = StoreApp.dataModel.productData.getProductData();
			columnNames = StoreApp.dataModel.productData.getColumnNames();
		}

		
		public int getRowCount() {
			return StoreApp.dataModel.productData.getProductNumbers();
		}

		public int getColumnCount() {
			return 0;
		}

		public Object getValueAt(int arg0, int arg1) {
			return null;
		}
		
		protected String[] getColumnNames() {
			return columnNames;
		}
		
		protected void setColumnNames(String[] columnNames) {
			this.columnNames = columnNames;
		}
		
		protected Object[][] getData() 	{
			return data;
		}
		
		protected void setData(Object[][] data) {
			this.data = data;
		}
	}
	
    class ButtonListener implements ActionListener {
		public void actionPerformed(ActionEvent e) {
			
			if (e.getActionCommand() == "neuer Datensatz") {

// hier habe ich diverse Dinge ausprobiert die allerdings alle nicht zur Folge hatten
				tmodel.insertRow(tmodel.getRowCount(), new Object[6]);
				//tmodel.addRow(new Object[6]);
				
				//in diese Schleife kam er nie rein aber wieso?
                                /*
				if( table.getModel() instanceof DefaultTableModel ){
					int cols = table.getModel().getColumnCount();
					table.getModel().addRow(new Object[cols]);
				 }
                                 */
				
				return;
			}
		}
	}
}

DefaultTableModel m = (DefaultTableModel)resultTable.getModel();
m.addRow(Object[] row); //oder 
m.addRow(Vector row);