ADDITIONAL SYSTEM INFORMATION :
I used JDK 19.0.2 on Debian GNU/Linux 11 (bullseye), Release 11 with installed RPM tools.


A DESCRIPTION OF THE PROBLEM :
The generated .spec file of jpackage does not check the context in the `preun` step.

When an application is updated by using the RPM executable, the new one is installed and then `preun` of the old installed application is run which would remove the desktop launcher after it was added.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
I generated a RPM installer with jpackage for our application.

When installing this RPM (dnf install) on a Fedora, a desktop launcher is generated (~/.local/share/applications/*.desktop).

When using the same RPM and running a reinstall (dnf reinstall), the new one is installed over the old one, but then the `preun` step of the old RPM is run and the desktop launcher is removed.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
On the `preun` step the context needs to be checked, if it is an uninstall or only an update of an already existing application. Something like:

case "$1" in
  0)
    xdg-desktop-menu uninstall ...
  ;;
esac
ACTUAL -
The context is not checked and therefore on an upgrade the desktop launcher is removed.

---------- BEGIN SOURCE ----------
https://github.com/ecsec/open-ecard

Running `./mvnw clean install -Ddesktop-package -Dpackage.type=RPM` will generate a corresponding RPM in `packager/richclient-packager/target/jpackage`

Then this RPM can be installed on a Fedora machine (dnf install) and then you can check that a desktop launcher should be available in `~/.local/share/applications/*.desktop`. If running a reinstall on the same RPM (dnf reinstall), the desktop launcher is removed.
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
We use the jpackage argument `--resource-dir` to provide a custom .spec file that does the context check (see fix above in expected result).

FREQUENCY : always