My colleague Jeff West pointed me to Stack Overflow today where someone had a question about how to take a thread dump when a certain condition was present. In their case, they are trying to troubleshoot a low thread count. Their monitoring tools were missing the critical time window and by the time the thread dump was taken, the threads had recovered. I thought this would be a great opportunity to see if a Diagnostic Image would contain a thread dump (yes it does), and whether I could automatically set WebLogic to create the Diagnostic Image easily when this condition was present (yes it is). Below is the image illustrating the issue they were trying to solve.
Check out this recording if you want to know more about triggering actions when certain conditions are met automatically with WebLogic Server. I show a WebLogic Diagnostic Framework (WLDF) System Module, configure a Notification and a Watch based on a JMX metric threshold. The Watch has with an Alarm with a manual reset (via JMX/WLST) so that the Watch will not fire again until I reset it although you can also choose not to have Alarms or have them reset automatically after a time period.
I encourage you to watch this video in 720p mode or higher for clarity. You can change that using the menu at the bottom right video widget. It will not display correctly in this blog template when using 720p mode.