Chris,

Thanks so much  for your suggestions!

We use Oracle version 19. I read the post you mentioned and found that this
warning message can be safely ignored. Please correct me if I'm wrong.

Thanks again!
Jenny



On Sat, Jun 1, 2024 at 7:57 AM Thomas Hoffmann (Speed4Trade GmbH)
<thomas.hoffm...@speed4trade.com.invalid> wrote:

> Hello Jenny,
>
> > -----Ursprüngliche Nachricht-----
> > Von: Ying Jin <jiny4...@gmail.com>
> > Gesendet: Samstag, 1. Juni 2024 00:18
> > An: Tomcat Users List <users@tomcat.apache.org>
> > Betreff: Re: Tomcat 9 memory leak message
> >
> > Chris,
> >
> > Thanks for your reply!
> >
> > We already removed the ojdbc8.jar file from the application's Web-inf/lib
> > folder as suggested in the following post, however, we still got the
> warning
> > messages below after the application is deployed to the Tomcat 9 server.
> >
> > https://stackoverflow.com/questions/6981564/why-must-the-jdbc-driver-be-
> > put-in-tomcat-home-lib-folder
> >
> > WARNING: The web application [Our Web Application Name] appears to have
> > started a thread named [InterruptTimer] but has failed to stop it. This
> is very
> > likely to create a memory leak. Stack trace of thread:
> >
> > WARNING: The web application [Our Web Application Name] appears to have
> > started a thread named [oracle.jdbc.diagnostics.Diagnostic.CLOCK] but has
> > failed to stop it. This is very likely to create a memory leak. Stack
> trace of
> > thread:
>
> I don't know which Oracle Version you are using.
> The JDBC-Driver seems to start some threads, but they are not stopped at
> shutdown of the application.
> One of the issues seems to be resolved in a newer version:
>
> https://stackoverflow.com/questions/78300946/how-to-not-run-or-stop-oracle-23-jdbc-driver-diagnostic-clock-thread
>
> >
> > I also read some posts saying these warning messages can be safely
> ignored if
> > the Tomcat version is greater than 7.0. I'm not sure if this is correct
> or not.
> >
> > Please advise,
> >
> > Many thanks!
> > Jenny
> >
> > On Fri, May 31, 2024 at 3:50 PM Christopher Schultz <
> > ch...@christopherschultz.net> wrote:
> >
> > > Jenny,
> > >
> > > On 5/31/24 14:52, Ying Jin wrote:
> > > > We removed the ojdbc8 driver jar from web-inf/lib from the web
> > > > application and kept the ojdbc8 jar file in the Tomcat/lib folder,
> > > > but we still can see the following memory link warning message
> > > > whenever we redeploy the web application. We use the Tomcat 9 server
> > > > in the Linux environment.
> > >
> > > This list strips attachments. Can you re-post with text-only?
> > >
> > > > The other warning message is about the "validateFile Problem with
> > > > jar file /tomcat/lib/jolokia.jar. My question is if we can safely
> > > > ignore these warning messages or not.
> > > >
> > > > It would be great if you can shed some light on this issue.
> > >
> > > If the message is something like "driver cannot be unloaded" then
> > > check Tomcat with a debugger or even something like JVisualVM to see
> > > how many WebappClassLoaders you have in memory.
> > >
> > > If the driver causes the web application ClassLoader to be "pinned" in
> > > memory, then it will never be removed and all those classes will
> > > continue to use-up heap space until you restart the JVM. This gets
> > > worse every time you reload your application without restarting the
> > > JVM. The Manager application web UI can help you diagnose these a
> little.
> > >
> > > The validation problem with the Jolokia JAR file will depend upon
> > > exactly what it says. I would first get a replacement copy of the
> > > Jolokia JAR file before bothering to try to diagnose it any further.
> > >
> > > -chris
> > >
> > > ---------------------------------------------------------------------
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> > >
> > >
>

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