Re: JBoss-related question

Håkan Jacobsson <hakan.jacobsson 'at' relevanttraffic.com> writes:

> Hi all,
>
> Thanx for your comments.
> Actually, yes, I've deployed without restarting JBoss a couple of times. It might be the cause.
> I've restarted the server now and doing some general testing.
>
> This might not solve the problem entirely though, since I tested stuff yesterday and all was fine.
> But today when doing some more testing - the exception suddenly
> was thrown. Without any 'hot re-deployments' (without any
> deployment actually) since I tested yesterday.

Notice that you can easily monitor the size of the permanent
generation with jmap[1]. It will be then very easy to confirm or
not that the deployment process is the rootcause of the out of
memory in the permanent generation space (whether by design -
normally IIRC a class is never unloaded from the permanent
generation - or because of a bug).

In our experience using Tomcat, for which we do *not*
undeploy/deploy applications but rather restart java altogether,
we had to raise the permanent generation (and it's been a stable
fix - it does not delay the problem). Seems that having a lot of
web applications contexts, each with its own jars (hence with
classes loaded separately), and using quite a few struts and jsp
classes, brings a significant amount of data in the permanent
generation.

Notice that even Sun's documentation specifically talks about the
potential need to increase the permanent generation when using
some JSP implementations[2].

Could you please return to this list about the results of your
investigations, whether there is a bug or an issue with
undeploying/deploying in jboss? Don't forget to tell the versions
of java and jboss you're using.

This is a bit offtopic but still quite interesting, I think.

Ref:
[1] http://zarb.org/~gc/html/doc-misc.html#2007-06-06

[2] http://java.sun.com/docs/hotspot/gc5.0/gc_tuning_5.html#1.1.Other%20Considerations%7Coutline

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