Issue Summary

This is reproducible on Data Center: Yes 

jdom2 Plugin exception is observed in logs after upgrade to Jira 9.0 or on a fresh installation. 

There is no issue/degradation in Jira Application functionality

Steps to Reproduce

1.  Install / upgrade to Jira 9.0.0 
2. Exception for plugin 'jdom2' is observed in the logs 

Expected Results

No exception thrown for the plugin. 

Actual Results

The below exception is thrown in the atlassian-jira.log file:

              Unloadable Reason                             : No plugin factories found for plugin file Unit: /opt/atlassian/jira/atlassian-jira/WEB-INF/atlassian-bundled-plugins/jdom2-2.0.6.1.jar (1655736172000) 

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available

There is no issue/degradation in Jira Application functionality and can be ignored