For some reason, the timestamp in my Tomcat logs is off. The system clock is correct, and set to PST, but the Tomcat logs appear to be using GMT. I haven't been able to find this setting anywhere...hoping someone can shed some light.
Thanks
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What version of Tomcat?– MattNov 18, 2009 at 18:16
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It's version 6.0.20– ThodyNov 18, 2009 at 19:22
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6 Answers
The JVM might have the wrong timezone set as a default.
Add a JVM option -Duser.timezone=US/Pacific (use the JAVA_OPTS property)
(also do a ps | grep java to look at the JVM command line and see if this option is already set for UTC, perhaps by a configuration setting or environment variable).
Most logging systems default to UTC. This keeps them readable across timezones.
It also allows you to mix logs from different timezones where applicable.
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I suppose that makes sense, although having Apache and Tomcat logging with different timezones, and the application correcting to yet another timezone makes troubleshooting a pain.– ThodyNov 18, 2009 at 17:12
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@Thody, I agree with that. Which is why everything should be in UTC and can be externally converted if necessary. Things get into trouble once timezones are introduced.– nikNov 18, 2009 at 17:21
Has the timezone of the system changed since Tomcat was started? I've had problems where Tomcat picks up the timezone when it first starts, and then refuses to accept a new reality until you kill it and start again.
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Nope, the system time has remained the same. I've actually restarted Tomcat several times as well.– ThodyNov 18, 2009 at 17:11
Java has its own implementation of the tzdata.
For instance, in my ubuntu servers, java's timezone definitions are in /usr/lib/jvm/java-6-sun-1.6.0.14/jre/lib/zi
While the system one are under /usr/share/zoneinfo/
You can specify which timezone java should use by passing the option -Duser.timezone=$TZ
where $TZ is the relative path to the timezone file under zi
for example: -Duser.timezone=Etc/GMT+3
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2It's better to use the named time zone rather than GMT+3. This allow for proper handling daylight savings time. In other words, use US/Pacific instead of GMT-8. Jan 1, 2010 at 18:36
It appears that Java uses the value in /etc/sysconfig/clock as the timezone value when starting up. On my system that was:
ZONE="America/New_York"
Change that value to what you want and restart tomcat.
I had a similar problem due to -Duser.timezone=UTC
You can expose this out with ps -edf | grep catalina if using Linux
