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Re: [Wrapper-user] Classload problems with inner classes. Was Re: Classes unloaded too early on process termination
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From: Chuck W. <ch...@ma...> - 2006-11-11 02:20:26
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Hi Leif,<br>
<br>
Thanks for your response. My latest wrapper.conf is attached.<br>
<br>
I user "Method 3" integration, i.e. a class that implements
WrapperListener.<br>
<br>
Here are a couple more anomalies I've noted:<br>
<ol>
<li>wrapper.restart.delay is not always honored. If the application
does Runtime.getRuntime().halt() then it works, but if the jvm halts on
its own (e.g., because of a SIGSEGV, which I was getting for a while),
or if wrapper does kill -9 on the jvm due to a ping timeout (see below)
then the restart delay is not honored. When the restart delay is not
honored, the restart frequently does not work. This is why I've
changed wrapper.on_exit.default to RESTART, which causes the failure to
start the jvm without restart delay to then get trapped for subsequent
jvm launch. Fortunately the restart delay is then honored and the
second launch attempt succeeds.<br>
<br>
</li>
<li>The jvm evidently does not respond to pings during a full gc.
I've gotten cases where the jvm is waiting too long to start full vc,
with little space left. This causes an abnormally long gc cycle, and
unloads some classes (although not the ones subject to the inner class
problem), ending up taking longer than the default 30 seconds. This is
why wrapper.ping.timeout is increased to 5 minutes.</li>
</ol>
<br>
I'll have to do a run with wrapper debug logging until I get one of the
occasional inner class problems. I've now noted these both on start-up
and shut-down. Occasionally the app is unable to load many classes
after start-up. This appears binary. Either many classes are missing,
or all is fine. If all is fine, there is never a subsequent problem
until shutdown, when the inner class issue can arise again.<br>
<br>
This problem first arose on the upgrade from wrapper 3.1.2 to 3.2.3. I
don't believe any other changes were involved, although it could be
coincidental of course. I.e., the issue could also exist in wrapper
3.1.2.<br>
<br>
The app does not use any native libraries other than wrapper. The rest
is pure java.<br>
<br>
Thanks for your help! I'll post a debug log file with the inner class
issue as soon as I can generate one.<br>
<br>
Chuck<br>
<br>
<br>
Leif Mortenson wrote on 11/10/2006 02:06 PM:
<blockquote cite="mid...@ta..." type="cite">
<pre wrap="">Chuck,
What integration method are you using? There were some minor
changes to the
WrapperStartStopApp concerning how it decides when to shutdown the JVM.
I don't
think that should have done anything to cause the problems you are seeing.
There are not any other changes that I can think of that could
possibly be causing
the problems you are seeing.
Were there any other changes to your application other than the
upgrade from 3.1.2
to 3.2.3?
Could you post your full wrapper.conf and a wrapper.log file with
wrapper.debug=true?
I may be able to get some clues from them.
Cheers,
Leif
Chuck Williams wrote:
</pre>
<blockquote type="cite">
<pre wrap="">The problem appears to be worse than described below. It appears that
certain inner classes are not loaded properly. I've only seen this
since upgrading to wrapper 3.2.3 from 3.1.2 Does wrapper do something to
affect class loading? Has anybody else experienced problems accessing
inner classes?
Thanks for any help,
Chuck
Chuck Williams wrote on 10/29/2006 11:19 AM:
</pre>
<blockquote type="cite">
<pre wrap="">Hi All,
After recently upgrading from wrapper 3.1.2 to 3.2.3 an anomaly has
developed in my application. When a normal kill signal is received on
linux (e.g., control-c when running from console) and
WrapperListener.stop() is called, occasionally classes are unloaded too
early, causing subsequent references to those classes in my shutdown
code to get NoClassDefFoundError. One time an inner class in my stop()
method itself got this error!
Can anyone explain or suggest a solution? Has anyone else seen this?
Thanks for any help,
Chuck
</pre>
</blockquote>
</blockquote>
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