Jira Issues Dates events' times are offset by an hour in Confluence Team Calendar
Platform notice: Server and Data Center only. This article only applies to Atlassian products on the Server and Data Center platforms.
Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.
*Except Fisheye and Crucible
Platform Notice: Data Center Only - This article only applies to Atlassian products on the Data Center platform.
Note that this KB was created for the Data Center version of the product. Data Center KBs for non-Data-Center-specific features may also work for Server versions of the product, however they have not been tested. Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.
*Except Fisheye and Crucible
Problem
In Confluence Team Calendar, any events of Jira Issue Dates event type would list the events date and time based on the user's timezone preference set in the User Profile. However, the listed time would be offset by an hour whenever we set the -Duser.timezone=Asia/Tokyo in Jira instance's JVM arguments.
Cause
Team Calendar uses ical4j library that applies its own timezone implementation, on top of the overridden JVM's timezone configured in Jira instance. Due to this, Jira would then returned event's time that are offset by an hour from the original event's time.
Workaround
To workaround this, we'd then need to add the following JVM parameter in Jira's setenv.sh file to disable iCal4j's TimeZone implementation and enforced the use of configured default Java timezone in Jira.
JVM_SUPPORT_RECOMMENDED_ARGS="-Duser.timezone=Asia/Tokyo -Dnet.fortuna.ical4j.timezone.update.enabled=false"
Please restart both Jira and Confluence instance after changing the JVM parameters accordingly.