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From Leon Rosenberg <>
Subject Re: Tomcat JVM using 99.9% cpu
Date Fri, 23 Sep 2005 06:11:39 GMT
It looks more like an infinite loop.
There are issues with tomcat, which causes infinite loops (see , but there
are also chances that you simply programmed one yourself in your code.
To check this, next time you tomcat has 99% cpu time, don't shut it down
but kill -quit <tomcats_pid>. It will then print a complete
stack-trace in the catalina.out (this isn't tomcat's feature, but
jvm's). Use the stacktrace to detect infinite loops.


On 9/23/05, Azariah Jeyakumar <> wrote:
> Hi,
> Has anyone seen Tomcat JVM using 99.9% cpu when there is no HTTP load at all? The JSP
pages are accessible fine without any loss in functionality, but the machine is sluggish (expectedly,
as the JVM is using all the CPU). If tomcat is restarted, the problem goes away and the CPU
usage returns to normal.
> I have not been able to reproduce the problem at will. It has been noticed only twice
or so in the past week, out of hundreds of attempts.
> I have seen other posts asking to tweak the settings like socket_* in
files. But since I have not been able to reproduce the problem at will, I am hesitant to change
the parameters, not knowing which change will fix the problem.
> Thanks for any input or pointers on:
> - the nature of the problem that causes this 99.9% CPU usage
> - how to reproduce the problem
> - what parameters should be set in file or elsewhere to avoid this
problem in the future.
> I am using Tomcat 5.0.28, Apache 2.x, jk2, Sun JRE 1.4.2_08  on Suse Linux Enterprise
Server (SLES 9 SP2).
> Thanks
> Azariah

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