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Class cache clean up question


I have an exclude defined in the JVM argument to exclude classes that starts with the word "fragment".


Looking at the IMAP files with the "ClassCacheImapDump60.jar" the fragment classes are still showing up in the file.

Should the excluded classes still show up in the IMAP files?



Hello John,

You will most likely see that classes until a week has passed. According to the documentation, the collector only clears week old classes.

"The Collector performs daily cleanup to keep the class cache from growing too large. The cache purges Classes not used for a week."


David Nicholls

I was under the impression that the exclude statement would not add the excluded classes to the IMAP file in order to prevent a class cache explosion. Is this incorrect?

Dynatrace Champion
Dynatrace Champion


as David already said: if the fragment classes have been added to the IMAP before the exclusion was added, it will take a week for them to be cleaned up by the Collector.

also: IMAPs always exist for a specific Agent Group, did you exclude those classes from all Agents within this Agent Group? and were all those Agents restarted afterwards?

HTH, Christian


Sorry, I did not clarify. The exclusion was added months ago to all agents in the agent group and they have been restarted several times since and I still see the classes in the IMAP file.

Here is the format of the JVM argument I am using:


Thank you