If your Jenkins instance is running in a different location than the user's (for example: the server is in NY but users are in LA), then the NY time zone will most probably be used, which may be quite annoying if you need to compare build dates.
To see the time zone used go to http://server/systemInfo and see the user.timezone system property.
If you cannot change the time zone of your server, then you can force jelly to use a given time zone for formatting time stamps.
So, you need to start your servlet engine with the following java system property :
java -Dorg.apache.commons.jelly.tags.fmt.timeZone=TZ ...
where TZ is a java.util.TimeZone ID ("Europe/Paris" for example).
Note that
user.timezone=Europe/Paris
will work as well, but it can interfer with other contexts.
If running Jenkins via a system package, this can be accomplished by setting JAVA_ARGS in your /etc/default/jenkins (Debian)
JAVA_ARGS="-Dorg.apache.commons.jelly.tags.fmt.timeZone=America/New_York"
or /etc/sysconfig/jenkins (Red Hat) such as:
JENKINS_JAVA_OPTIONS="-Dorg.apache.commons.jelly.tags.fmt.timeZone=America/New_York"
or, if that doesn't work,
JENKINS_JAVA_OPTIONS="-Duser.timezone=America/New_York"
(note that underscores in timezone names are important) and then restarting Jenkins via the init script (not via the UI).
On FreeBSD, the file to edit is /etc/rc.conf, and the option to use is:
jenkins_java_opts="-Dorg.apache.commons.jelly.tags.fmt.timeZone=America/Indiana/Indianapolis"
On windows, edit %INSTALL_PATH%/jenkins/jenkins.xml. Note, put "-Dargs" before "-jar".
<arguments>-Xrs -Xmx256m -Duser.timezone="Europe/Minsk" -Dhudson.lifecycle=hudson.lifecycle.WindowsServiceLifecycle -jar "%BASE%\jenkins.war" --httpPort=8080</arguments>
From the Jenkins Script Console on a live system without the need for a restart which can also be included in a Post-initialization script to make it permanent.
System.setProperty('org.apache.commons.jelly.tags.fmt.timeZone', 'America/New_York')