Classloader leak in atlassian-plugins-2.3.1

A classloader leak has been found where a commons-logging Log instance is created per instance of the DefaultServletModuleManager class rather than statically. The class is loaded by the application class loader but the instance may be loaded from within an OSGi bundle.

This is only a problem when:

1. The class has been used (and therefore loaded) and then
2. A full data-import is performed

If this happens then a small amount of permgen is leaked to a now redundant classloader that is still referenced from commons-logging.

In practice this only really happens during functional testing, specifically the Fisheye Plugin functional tests. It is unlikely to cause customers any problem in practice and if it does, the workaround is to restart JIRA.

The fix is in atlassian-plugins-2.3.2 and above. We need to upgrade the plugins version. Details can be found here.