Apache – Tomcat showing this error “This is very likely to create a memory leak”. How to resolve this issue

apacheapache-cocoon

I have created a web application in Apache Cocoon.This website is running properly but after every 3-4 days, it stops responding. It doesn't run until and unless, we restart the tomcat service. In the catalina.2011-05-09.log file, it shows following error:-

"May 9, 2011 3:17:34 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/webresources] is still processing a request that has yet to finish. This is very likely to create a memory leak. You can control the time allowed for requests to finish by using the unloadDelay attribute of the standard Context implementation."

I am not been able to understand the cause of this problem. Can someone suggest me how to resolve this issue?

Best Answer

You are using a library that is starting one or more threads and is not properly shutting them down or releasing other resources captured by the thread. This often happens with things like Apache HTTP components (I get this error with Http Components) and anything that uses separate threads internally. What libraries are you using in your Cocoon application?

Related Solutions

Apache – How to create “Aliases” in Apache Tomcat

I spent a lot more time researching this and found a solution that solves the random deletion of the context files. I found this excerpt on Apache's website under the host configuration section:

You can nest one or more Context elements inside this Host element, each representing a different web application associated with this virtual host.

The virtual hosts are stored in the server.xml file located at CATALINA_HOME\conf. Tomcat comes configured with localhost as the default host. So, if we add the contents of attachments.xml from the first post, we get the following:

<Host name="localhost"  appBase="webapps"
    unpackWARs="true" autoDeploy="true"
    xmlValidation="false" xmlNamespaceAware="false">

    <Context path="/attachments"
             docBase="e:\uploads\attachments"
             reloadable="true"
             crossContext="true" />
</Host>

This is as close as one can get to defining aliases similar to Apache's HTTP server, I think.

Spring – Is this very likely to create a memory leak in Tomcat

The message is actually pretty clear: something creates a ThreadLocal with value of type org.apache.axis.MessageContext - this is a great hint. It most likely means that Apache Axis framework forgot/failed to cleanup after itself. The same problem occurred for instance in Logback. You shouldn't bother much, but reporting a bug to Axis team might be a good idea.

Tomcat reports this error because the ThreadLocals are created per HTTP worker threads. Your application is undeployed but HTTP threads remain - and these ThreadLocals as well. This may lead to memory leaks (org.apache.axis.MessageContext can't be unloaded) and some issues when these threads are reused in the future.

For details see: http://wiki.apache.org/tomcat/MemoryLeakProtection

Best Answer

Related Solutions

Apache – How to create “Aliases” in Apache Tomcat

Spring – Is this very likely to create a memory leak in Tomcat

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