RE: clearReferencesThreads issues warning about 2 threads, spawned by JDK in printing components

[jo...@wellsfargo.com.INVALID]

Thanks Mark,

Unfortunately the URL in the error gets blocked by our security, so I looked it up on my home system now.



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> -----Original Message-----
> From: Mark Thomas <ma...@apache.org>
> Sent: Monday, August 23, 2021 3:06 AM
> To: users@tomcat.apache.org
> Subject: Re: clearReferencesThreads issues warning about 2 threads,
> spawned by JDK in printing components
> 
> On 23/08/2021 08:10, Thomas Hoffmann (Speed4Trade GmbH) wrote:
> 
> <snip/>
> 
> > Is there anything, the application can prevent this?
> 
> Yes. Call Thread.setContextClassLoader(ClassLoader) before calling the code
> that creates those threads, passing the common class loader.
> Afterwards, reset the TCCL back to the web application class loader.
> 
> > Should Tomcat maybe skip the warning if the thread is demonized?
> 
> No. The threads have the web app class loader as their TCCL so you have a
> potential memory leak. The warning is correct.
> 
> > Or maybe these threads should be ignored when checking for orphaned
> threads?
> 
> No, for the same reason.
> 
> > It was tested with Tomcat 9.0.52, Windows 10, Coretto-JDK 11.0.12_7.
> 
> You might want to consider raising a bug against the JDK. It could be argued
> that those threads should be created with a specific class loader to avoid
> memory leaks in container environments.
> 
> Mark
> 
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