When/how does the UNinstaller get called?

Question

This simple demo. of using the ExtensionInstallerService
has me confused..
http://www.physci.org/jws/application.jnlp
It behaves as I expect on installation.
At time of installation, the user is prompted to
accept a psuedo 'license agreement'.
If they accept it, the application is launched.
If they refuse it, it is not launched.
If they refuse it, they can try again later and
the EULA dialog will be shown again, and
will continue to be shown, each launch, as
many times as the user refuses it.
But how/when is the uninstall option called?
In this example, I used the uninstaller option
simply to thank the user for using the application.
However, I do not ever see the 'thanks' dialog.
So far I have tried uninstalling the app. from both
the Java Control Panel, as well as Windows own
Add/Remove Programs dialog.
Does it work for anybody else?
The source for the installer that I am currently
using is as follows.
package test;
import javax.swing.*;
// classes of the web-start API, used in this example.
import javax.jnlp.ExtensionInstallerService;
import javax.jnlp.ServiceManager;
import javax.jnlp.UnavailableServiceException;
class Installer {
  Installer() {
    try {
      ExtensionInstallerService installerService =
        (ExtensionInstallerService)ServiceManager.
          lookup("javax.jnlp.ExtensionInstallerService");
      /* We do not need the progress bar as progress
      is determined by the user accepting the EULA.
      They can consider it as long as they like. */
      installerService.hideProgressBar();
      int result = JOptionPane.showConfirmDialog(null,
        "Do you agree to the EULA?",
        "End User License Agreement",
        JOptionPane.YES_NO_OPTION,
        JOptionPane.QUESTION_MESSAGE );
      boolean agree = (result==JOptionPane.YES_OPTION);
      if (agree) {
        installerService.installSucceeded(false);
      } else {
        JOptionPane.showMessageDialog(null,
          "Perhaps another time..");
        installerService.installFailed();
    } catch (UnavailableServiceException e) {
      e.printStackTrace();
  public static void main(String[] args) {
    if ( args[0].equals("install") ) {
      Installer installer = new Installer();
    } else {
      /* No need to do anything on uninstall,
      but thank the user for their patronage */
      JOptionPane.showMessageDialog(null,
        "Thank you for using (Trivial) Application!");
}

Answer 1

I submitted a Bug Report for this, under the title..
installer-desc UNinstaller never called
The basic gist of it is..
Java web start (JWS) offers the installer-desc
element to identify an installer/uninstaller
for an application. The intent of the installer
is to do any application set-up/pull-down that
can not be handled by the standard JWS behaviour
of caching the classes/resources at 1st launch,
and clearing them at uninstall.
The 'install' side of the installer-desc element
seems to work as advertised, but as has been noted
in the web start forum a number of times*, the
installer is never called at time of 'uninstall'.
* Though none reported successful resolution of
the problem, it also seems no one took it through
to a bug report.
http://forum.java.sun.com/thread.jspa?forumID=38&threadID=5124101
(one report)
http://forum.java.sun.com/thread.jspa?threadID=790898
(two relatively recent reports)
http://forum.java.sun.com/thread.jspa?forumID=38&threadID=263691
(1 report from June 2002)