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While it might be possible to make the shutdown experience a little
more graceful, your expectation of being able to use the GUI after
the start of the shutdown sequence is unlikely to be met. Quoting
from the shutdown docs [1] :<br>
<br>
"Shutdown hooks run at a delicate time in the life cycle of a
virtual machine ... Attempts to use other thread-based services such
as the AWT event-dispatch thread, for example, may lead to
deadlocks.<br>
<br>
Shutdown hooks should also finish their work quickly. When a program
invokes exit, the expectation is that the virtual machine will
promptly shut down and exit. When the virtual machine is terminated
due to user logoff or system shutdown the underlying operating
system may only allow a limited amount of time in which to shut down
and exit. <b>It is therefore inadvisable to attempt any user
interaction or to perform a long-running computation in a shutdown
hook.</b>"<br>
<br>
Note, particularly, that last sentence. Asking JavaFX to ignore the
fact that there is a shutdown in progress doesn't change that.
Having said that, I can take another look at this (not right away,
though) and see what else we can do.<br>
<br>
-- Kevin<br>
<br>
[1]
<a class="moz-txt-link-freetext" href="https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/Runtime.html#addShutdownHook(java.lang.Thread)">https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/Runtime.html#addShutdownHook(java.lang.Thread)</a><br>
<br>
<br>
<div class="moz-cite-prefix">On 7/26/2024 10:11 AM, PavelTurk wrote:<br>
</div>
<blockquote type="cite" cite="mid:015ba9f6-e266-4fb3-bda0-32654f12af23@gmail.com">Hello,
Kevin
<br>
<br>
Yes, I filed that enhancement request.
<br>
<br>
When user presses CTRL+C then SIGINT signal is sent to the
process. SIGINT is a signal used to request a graceful termination
of a process, typically initiated by the user(more details are
here
<a class="moz-txt-link-freetext" href="https://urldefense.com/v3/__https://stackoverflow.com/a/4047975__;!!ACWV5N9M2RV99hQ!Kubf8U462HbtwSv0HaNgAZNyYpFS94_WfV0T8TAjTcNx56xb2lUr9jPR5ezZHSUjZ1C-tStV9j5KxWUduzx7XjC0BR1D$">https://urldefense.com/v3/__https://stackoverflow.com/a/4047975__;!!ACWV5N9M2RV99hQ!Kubf8U462HbtwSv0HaNgAZNyYpFS94_WfV0T8TAjTcNx56xb2lUr9jPR5ezZHSUjZ1C-tStV9j5KxWUduzx7XjC0BR1D$</a>
).
<br>
<br>
Now, we are talking about GUI application (if we didn't develop a
GUI application, we wouldn't need JavaFX, would we?). So, our GUI
application gets SIGINT or SIGTERM (I didn't test with SIGTERM,
but I think result is the same) and after that immediately stops
working because of the damned shutdown hook. For example, if our
application is a simple text editor, our application can't let
user save file. Why? Because GUI platform doesn't work anymore.
<br>
<br>
That's why I opened that issue. I saw you suggested working with
exceptions. But that issue is not about exceptions, but about
letting application developers control when to shutdown platform.
<br>
<br>
Best regards, Pavel
<br>
<br>
<br>
On 7/26/24 16:54, Kevin Rushforth wrote:
<br>
<blockquote type="cite">I am not sure we will want to disabling
the shutdown hook, since that is likely to cause problems (they
were added to fix bugs that resulted from applications calling
System.exit()).
<br>
<br>
In the bug report for JDK-8320923, you mentioned that Swing
doesn't have this problem, but that's because Swing closes all
of its windows before effecting the shutdown (that's something
JavaFX could do as well).
<br>
<br>
Related to this, I see that someone (perhaps it was you?) just
filed an enhancement request to consider optionally disabling
the shutdown hook:
<br>
<br>
<a class="moz-txt-link-freetext" href="https://bugs.openjdk.org/browse/JDK-8337247">https://bugs.openjdk.org/browse/JDK-8337247</a>
<br>
<br>
I haven't looked at it closely, but my sense is that disabling
the shutdown hooks in a way that tries to keep the JavaFX
runtime active is unlikely to be something we want to do. I
added the following comment to the above JBS issue with some
initial thoughts:
<br>
<br>
--------------------------------------------------
<br>
“I can take a look, but I do not think we will implement this
Enhancement request -- at least not as described.
<br>
<br>
Instead, we might consider whether this can be done using
existing mechanisms, such as overriding Application::exit. If it
turns out there isn't a suitable existing mechanism, we might
consider other solutions. A couple possibilities:
<br>
<br>
1. Provide a Platform setting that will cause Platform.runLater
to throw an exception if called after shutdown (this might be
require adding a few try/catch blocks in our own cleanup code)
<br>
2. Rather than a setting as described above, create a new
overload of Platform.runLater that throws an exception if the
Platform is not able to queue the request.
<br>
<br>
There might be other solutions.”
<br>
-------------------------------------------------------
<br>
<br>
-- Kevin
<br>
<br>
<br>
On 7/25/2024 8:43 AM, PavelTurk wrote:
<br>
<blockquote type="cite">Hello all.
<br>
<br>
JavaFX adds its own shutdown hook. That gives many problems
when it is necessary to work with application,
<br>
when system is shutting down, for example, if user presses
CTRL+C. The first problem I described here -
<br>
<a class="moz-txt-link-freetext" href="https://bugs.openjdk.org/browse/">https://bugs.openjdk.org/browse/</a>
<br>
<br>
Another problem is that after pressing CTRL+C JavaFX seems not
to respond anymore. For example I've
<br>
observed that if after that we try to do Platform.runLater(()
-> myCode is here), then myCode will never execute.
<br>
So, it is necessary to check in system, how it is shutting
down, if it is. And this problem creates other problems.
<br>
<br>
Before opening a feature request, I decided to ask JavaFX
developers, if it possible to disable JavaFX shutdown hook.
<br>
I mean, if there is no system property (something like
javafx.shutdownhook.disabled), it will be added, but if I want
<br>
to call Platform.exit() manually I want to be able to disable
JavaFX shutdown hook.
<br>
<br>
Best regards, Pavel
<br>
<br>
</blockquote>
<br>
</blockquote>
<br>
</blockquote>
<br>
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