JTable bean in forms

Question

I would like to display JTable based bean in Oracle Forms 10g but I get:
*** VBean null PropertyManager for id = FOREGROUND
*** VBean Got FOREGROUND = null
*** VBean null PropertyManager for id = BACKGROUND
*** VBean Got BACKGROUND = null
*** VBean Setting debugMode to ALL
*** VBean Setting beanName to plusplus.PPCalendar
*** plusplus.PPCalendar Registering properties
*** plusplus.PPCalendar     int pWidth
*** plusplus.PPCalendar     int pDebugGraphicsOptions
*** plusplus.PPCalendar     int pHeight
*** plusplus.PPCalendar     boolean pOpaque
*** plusplus.PPCalendar     javax.swing.InputVerifier pInputVerifier
*** plusplus.PPCalendar     Failed to introspect class: class plusplus.PPCalendar java.lang.NullPointerExceptionPPCalendar's code:
public class PPCalendar extends JPanel
  private JTable table;
  private DefaultTableModel model;
  private JScrollPane jsp;
public PPCalendar() {
   super();
   model = new DefaultTableModel( new String[] [] {  {"1x1", "1x2"},  {"2x1", "2x2"}}, new String [] {"First", "Second"});
   table = new JTable(model);
   jsp = new JScrollPane(table);
   jsp.setAutoscrolls(true);
   this.add(jsp);
   this.setVisible(true);
  public void setHead(String nes) {
    String val1 = (String) model.getValueAt(0,0);
    System.out.println("val1: " + val1);
  public String getHead() {
    return (String) model.getValueAt(0,0);
  }Setting property (     fbean.set_property('tb.ptable', 1, 'head', 'Blah');) fails, but I can set properties (introspection still fails) if I try something similar with:
package plusplus;
//import java.awt.Panel;
//import java.awt.Label;
import javax.swing.JPanel;
import javax.swing.JLabel;
public class Simple extends JPanel  {
  private JLabel naziv = new JLabel();
  public Simple() {
    try {
      jbInit();
    } catch(Exception e) {
      e.printStackTrace();
  private void jbInit() throws Exception {
    naziv.setText("XXX");
    this.add(naziv, null);
  public void setNaziv(String tekst) {
    naziv.setText(tekst);
}What am I doing wrong? Are there some "more advanced" swing based bean examples?
Is there some kind of documentation on oracle.ewt.* and Dynamic Bean Manager?

Answer 1

The problem is that you're extending JPanel - the issue is not your fault (or ours for that matter) it's a problem in the base JPanel class which causes a NPE when introspecting the properties that it exposes because it does not conform to the JavaBeans Spec.
We've put a WorkAround into the FBean code in Forms 10.1.2 but for the moment you will have to extend Panel rather than JPanel and all should be ok - this should make no difference to the operation of the Bean.
Another option would be to write a BeanInfo class for your Bean and prevent the exposure of the problem property (inputMap) that way.