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From André Warnier>
Subject Re: Please help ... [MultiThreadedHttpConnectionManager cleanup]
Date Wed, 24 Nov 2010 14:49:42 GMT
Emerson, Christopher wrote:
> Ever since we've upgraded to Tomcat 6 4 weeks ago, I've been fighting
> the following error on shutdown ...
> Nov 23, 2010 4:42:18 PM org.apache.catalina.loader.WebappClassLoader
> clearReferencesThreads
> SEVERE: A web application appears to have started a thread named
> [MultiThreadedHttpConnectionManager cleanup] but has failed to stop it.
> This is very likely to create a memory leak.
> We're using Tomcat 6.0.29 and it reproduces on both Windows and Linux.
> The application uses commons-httpclient-3.1.  I've done so many
> different things to shut down the connection from the web application
> that I'm convinced that it is either something with the
> commons-httpclient-3.1 or Tomcat 6.  Since this did not happen with
> Tomcat 5, I'm leaning towards Tomcat 6 problem.

Let me see if I have got this right..

The reason why you are seeing the message above in Tomcat 6, and were not seeing it in 
Tomcat 5, is because in Tomcat 6 there is added code which detects this kind of thing, and

prints messages in the logs about it.
Under Tomcat 5, the root reason happened too, but was not detected so you just did not 
know about it.

If really this happens only when you shut down Tomcat, I don't think it should matter, 
since you are stopping the whole JVM, including that rogue thread, the memory will get 
cleaned up and there will be no leak left anyway.

The message is there in case you would just stop and restart this application, without 
stopping the JVM in-between.  Then you would experience a memory leak, and then it could 
matter in the long run.

This being said, it does indicate a cause for possible memory leaks in the future, so you

/might/ want to investigate further.

How am I doing ?

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