Memory leak messages when shutdown Tomcat container

[Edwin B.]

Hi,

We have noticed some alarming warnings in catalina.out (see stacktrace below) after shutdown/restarting our Tomcat container (Hippo 10.2.0 / Tomcat 8.0.32 / MySQL 5.6.29).

Has anyone seen these messages before / a clue where they come from?

Best regards,

Edwin

07-Apr-2016 13:10:54.391 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [cms] appears to have started a thread named [Abandoned connection cleanup thread] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.lang.Object.wait(Native Method)
 java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
 com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:43)
07-Apr-2016 13:10:54.392 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [cms] appears to have started a thread named [Transient File Reaper] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.lang.Object.wait(Native Method)
 java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
 java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164)
 org.apache.jackrabbit.util.TransientFileFactory$ReaperThread.run(TransientFileFactory.java:192)
07-Apr-2016 13:10:54.393 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [cms] appears to have started a thread named [Wicket-PageSavingThread] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
 java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
 org.apache.wicket.pageStore.AsynchronousDataStore$PageSavingRunnable.run(AsynchronousDataStore.java:345)
 java.lang.Thread.run(Thread.java:745)
07-Apr-2016 13:10:54.394 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [cms] appears to have started a thread named [Wicket-PageSavingThread] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
 java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
 org.apache.wicket.pageStore.AsynchronousDataStore$PageSavingRunnable.run(AsynchronousDataStore.java:345)
 java.lang.Thread.run(Thread.java:745)

[marijan milicevic]

Hi Edwin,

On Thu, Apr 7, 2016 at 3:22 PM, Edwin B. <ett...@gmail.com> wrote:

Hi,

We have noticed some alarming warnings in catalina.out (see stacktrace below) after shutdown/restarting our Tomcat container (Hippo 10.2.0 / Tomcat 8.0.32 / MySQL 5.6.29).

Has anyone seen these messages before / a clue where they come from?

they come if you reload application (without restarting container, in your case, tomcat)

cheers

marijan

 

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[Edwin B.]

Hi Marijan,

They come when stopping Tomcat-container. That's true.

But will it do any harm?

Best regards,

Edwin

On Thursday, April 7, 2016 at 3:36:45 PM UTC+2, marijan milicevic wrote:

Hi Edwin,

[Jasper Floor]

This happens in Tomcat when you stop an application with threads and thread local variables. It's a tomcat thing and you can ignore it. If it happens other than when you stop tomcat then you need to take action. On shutdown it's perfectly safe to ignore.

mvg,

Jasper

--

[Edwin B.]

Hi Jasper,

On Friday, April 8, 2016 at 11:45:54 AM UTC+2, Jasper Floor wrote:

This happens in Tomcat when you stop an application with threads and thread local variables. It's a tomcat thing and you can ignore it. If it happens other than when you stop tomcat then you need to take action. On shutdown it's perfectly safe to ignore.

Thanks for your reply.

Do you know if there is a way to avoid these warnings? Change of configuration, file location, version of the mysql-connector....?

We'd like to keep our log-files as clean as possible...

Best regards,

Edwin

 

mvg,

Jasper

[Jasper Floor]

I am not aware of a way to avoid these warnings but I've never really looked into that,  just whether it was something to worry about. I wouldn't want to prevent the logging altogether as it could signal an actual problem. This is Tomcat trying to be helpful but on shutdown it gets hard to keep things straight. I agree that it is annoying (at the least) to have to ignore this in log files. 

mvg,

Jasper