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From Leon Rosenberg <rosenberg.l...@gmail.com>
Subject Re: how can i turn off "This is very likely to create a memory leak."
Date Thu, 28 Oct 2010 15:51:54 GMT
On Thu, Oct 28, 2010 at 4:19 PM, Simon Funnell
<simon.funnell@propositum.biz> wrote:
> On 28/10/10 14:53, Leon Rosenberg wrote:
>>
>> ok, i revoke my "nevermind" message, even after I removed
>> JreMemoryLeakPreventionListener
>> I still get the warning. Even weirder:
>>
>> Oct 28, 2010 3:50:55 PM org.apache.catalina.core.StandardService stop
>> INFO: Stopping service Catalina
>> Oct 28, 2010 3:50:55 PM org.apache.catalina.loader.WebappClassLoader
>> clearReferencesThreads
>> SEVERE: The web application [/moskitodemo] appears to have started a
>> thread named [Poller SunPKCS11-Darwin] but has failed to stop it. This
>> is very likely to create a memory leak.
>>
>
> Note the word 'likely' is not 'defiantly', it is possible that your
> implementation is 'not' creating a memory leak.
>

but a SEVERE log message should be pretty sure and not likely.

> If tomcat launches an independent thread (not a tomcat thread) that refers
> to objects within the tomcat instance (and its pool of threads), this is
> when a memory leak would occur.
>
> This is because objects referenced by the independent thread 'and' the
> tomcat instance would not be GC'ed when tomcat shuts down, because they are
> still referenced by a living thread.

I really don't get it. I'm stopping tomcat. What do I care about
objects living in a webapp which is DEAD in a second in a VM which
will be dead in another second?

>
> 'Generally' you will want to stop the independent threads when tomcat shuts
> down, thus removing the 'likelihood' of memory leaks.

No actually I don't care. If they have jobs to do, they are free to
define their shutdown hooks. Otherwise all daemon threads are
automatically killed if the vm is killed.

>
> If the independent threads have their own shut down hooks that realise
> tomcat is shutting down and dereference any appropriate objects, a memory
> leak will 'not' occur.
>
> If you want your independent threads to shut down with tomcat because they
> do not have the own mechanisms, implement a
> ServletContextListener.contextDestroyed that does so.

Yeah, but I actually don't. I mean I'm hitting ctrl-c in a terminal
with running bin/catalina.sh run.
I just want to get rid of the message to prevent the admins from
jumping up and down cause they detect a SEVERE message in the logs...
regards
Leon


>
> Regards,
>
> Simon
>
>> Oct 28, 2010 3:50:55 PM org.apache.catalina.loader.WebappClassLoader
>> clearReferencesThreads
>> SEVERE: The web application [/moskitodemo] appears to have started a
>> thread named [MoskitoIntervalUpdater] but has failed to stop it. This
>> is very likely to create a memory leak.
>> Oct 28, 2010 3:50:55 PM org.apache.catalina.loader.WebappClassLoader
>> clearReferencesThreads
>> SEVERE: The web application [/moskitodemo] appears to have started a
>> thread named [MoskitoMemoryReader] but has failed to stop it. This is
>> very likely to create a memory leak.
>> Oct 28, 2010 3:50:55 PM org.apache.catalina.loader.WebappClassLoader
>> clearReferencesThreads
>> SEVERE: The web application [/moskitodemo] appears to have started a
>> thread named [MoskitoMemoryPoolReader] but has failed to stop it. This
>> is very likely to create a memory leak.
>> Oct 28, 2010 3:50:55 PM org.apache.catalina.loader.WebappClassLoader
>> clearReferencesThreads
>> SEVERE: The web application [/moskitodemo] appears to have started a
>> thread named [MoskitoMemoryPoolReader] but has failed to stop it. This
>> is very likely to create a memory leak.
>> Oct 28, 2010 3:50:55 PM org.apache.catalina.loader.WebappClassLoader
>> clearReferencesThreads
>> SEVERE: The web application [/moskitodemo] appears to have started a
>> thread named [Thread-6] but has failed to stop it. This is very likely
>> to create a memory leak.
>> Oct 28, 2010 3:50:56 PM org.apache.coyote.http11.Http11Protocol destroy
>> INFO: Stopping Coyote HTTP/1.1 on http-8080
>>
>> anyplace else except the server.xml to fix it?
>>
>> regards
>> Leon
>>
>> On Thu, Oct 28, 2010 at 3:46 PM, Leon Rosenberg
>> <rosenberg.leon@gmail.com>  wrote:
>>
>>>
>>> nevermind, found it, sorry for disturbing.
>>>
>>> On Thu, Oct 28, 2010 at 3:44 PM, Leon Rosenberg
>>> <rosenberg.leon@gmail.com>  wrote:
>>>
>>>>
>>>> Hello,
>>>>
>>>> I investigated an issue (another thread) with new error messages after
>>>> tomcat update:
>>>>
>>>> SEVERE: The web application [/moskitodemo] appears to have started a
>>>> thread named [MoskitoMemoryPoolReader] but has failed to stop it. This
>>>> is very likely to create a memory leak.
>>>>
>>>>
>>>> After some research and discussions with colleagues we came to the
>>>> conclusion that this message is ... well not helping us. Is there a
>>>> possibility to turn it off? Its annoying to have such messages in the
>>>> logs
>>>> after a server shutdown. For explanation: I'm not planing to use
>>>> webapp reload in my environment, hence, this message is actually just
>>>> spam.
>>>>
>>>> regards
>>>> Leon
>>>>
>>>>
>>>
>>>
>>
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>>
>
>
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