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Re: [jetty-users] java.lang.OutOfMemoryError: PermGen space

You may be interested in adding one more tool for solving memory leaks into your toolbox: http://plumbr.eu . We have tried to explain the reasons behind class loader leaks in some of our blog posts: https://plumbr.eu/blog/what-is-a-permgen-leakhttps://plumbr.eu/permgen to name a few...

Nikita Salnikov-Tarnovski
@iNikem/@JavaPlumbr


On 30 April 2014 21:14, Andrew Eidsness <eclipse@xxxxxxxxxx> wrote:
Moving the postgres driver out of the .war file seems to have fixed my problem.  I think that is a good change anyhow.
It was only really added to the .war because it was convenient at the time.

I hadn't noticed the DriverManagerLeakPreventer when I first looked through the list (probably because at that time I
didn't realize that it was the problem).  I assume it would solve the problem as well.

Mattias' preventer looks interesting too, I've added it to my list of things to try out.  Thanks.

-Andrew

On 14-04-30 01:40 PM, Hal Deadman wrote:
> I think this (https://github.com/mjiderhamn/classloader-leak-prevention) is the most comprehensive (and application
> server independent) listener for preventing classloader memory leaks.
> I agree that not packaging the database driver with the web app is a good idea although the listener should clean up
> that particular leak.
>
> The classloader-leak-prevention listener's author also has a good series discussing classloader leaks (why they happen
> and how to track them down) on his blog: http://java.jiderhamn.se/
>
>
>
> On Wed, Apr 30, 2014 at 1:21 PM, Joakim Erdfelt <joakim@xxxxxxxxxxx <mailto:joakim@xxxxxxxxxxx>> wrote:
>
>     Could the DriverManagerLeakPreventer help?
>     https://github.com/eclipse/jetty.project/blob/master/jetty-util/src/main/java/org/eclipse/jetty/util/preventers/DriverManagerLeakPreventer.java
>
>     It will pin the DriverManager at the server side classloader.
>
>
>     --
>     Joakim Erdfelt <joakim@xxxxxxxxxxx <mailto:joakim@xxxxxxxxxxx>>
>     webtide.com <http://www.webtide.com/> - intalio.com/jetty <http://intalio.com/jetty>
>     Expert advice, services and support from from the Jetty & CometD experts
>     eclipse.org/jetty <http://eclipse.org/jetty/> - cometd.org <http://cometd.org/>
>
>
>     On Wed, Apr 30, 2014 at 9:31 AM, Andrew Eidsness <eclipse@xxxxxxxxxx <mailto:eclipse@xxxxxxxxxx>> wrote:
>
>         Jetty is deployed on my server and is running as a stand-alone daemon.  I'm deploying the war by copying into the
>         webapps folder.
>
>         Following the class loader references I think the problem is that java.sql.DriverManager.registeredDrivers is
>         keeping an
>         instance of my org.postgresql.Driver from each deployed instance.  The registeredDrivers member is an ArrayList
>         of with
>         8 instances of java.sql.DriverInfo each holding an instance of org.postgresql.Driver.  DriverManager was loaded
>         by the
>         system class loader but the postgres Driver was loaded by the webapp's loader.
>
>         I think the fix is to stop deploying my postgres connector as part of the webapp.  I don't have a real reason for
>         deploying it that way, it was just for convenience when I was setting up the project.  I'll copy it into my jetty
>         deployment instead and see what happens.
>
>         Thanks for your help.  My main problem here is not being confident in how I've setup things.  I've used Google
>         to find
>         documentation for small parts of various versions.  However, I think I'm making progress now.
>
>         -Andrew
>
>         On 14-04-30 11:48 AM, Jan Bartel wrote:
>         > Andrew,
>         >
>         > How are you running jetty? In a standalone distro, as the maven
>         > plugin, or via embedded code? I take it that the webapp is being
>         > unpacked to a tmp directory?
>         >
>         > It does sound as if the WebAppClassloader is being pinned. There
>         > should be a way with the heap dump tool to follow back to the objects
>         > that  are keeping  references to the WebAppClassLoaders, or follow the
>         > link from the doc page to the blog entry about classloader pinning,
>         > which describes how to use JVisualVM to hunt down the references.
>         >
>         > Jan
>         >
>         >
>         >
>         > On 1 May 2014 01:11, Andrew Eidsness <eclipse@xxxxxxxxxx <mailto:eclipse@xxxxxxxxxx>> wrote:
>         >> My jetty server (9.1.4.v20140401) eventually runs out of memory after I’ve
>         >> deployed the same war (during development) to the webapps folder. After
>         >> looking in the bugs database I think this might be happening because I’m
>         >> deploying jars inside the war’s lib folder.
>         >>
>         >> The reason I think this is that looking at the heap dump (in MAT) I can see
>         >> 8 copies of classes from those bundled jars. Each of the instances was
>         >> loaded by a different instance of
>         >> org.eclipse.jetty.webapp.WebAppClassLoader.
>         >>
>         >> My theory is that when the war is redeployed a new instance of
>         >> WebAppClassLoader is created which then loads the new jar files.
>         >>
>         >> I think I’m doing something wrong, but haven’t been able to figure out what.
>         >> I’m not sure how to get the old class loader’s to go away.
>         >>
>         >> I’ve tried using the leak preventer
>         >> (http://www.eclipse.org/jetty/documentation/current/preventing-memory-leaks.html)
>         >> by putting this into my jetty.xml file:
>         >>
>         >> <Call name="addBean">
>         >>     <Arg>
>         >>         <New
>         >> class="org.eclipse.jetty.util.preventers.AppContextLeakPreventer"/>
>         >>     </Arg>
>         >> </Call>
>         >>
>         >> But it didn’t seem to make a difference.
>         >>
>         >> Any ideas or pointers to appropriate documentation?
>         >>
>         >> Thanks,
>         >> -Andrew
>         >>
>         >>
>         >> _______________________________________________
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>         >>
>         >
>         >
>         >
>
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