Sightly duplicate classes seen in heapdump when OutOfMemory: Metaspace errors occur

HTL (aka Sightly) duplicate classes are observed in heap dumps when java.lang.OutOfMemoryError: Metaspace errors occur.

Environment

AEM 6.1

Cause

Defects in the SLING JavaScript scripting engine [1],[2].

[1] https://issues.apache.org/jira/browse/SLING-4787
[2] https://issues.apache.org/jira/browse/SLING-4783
 

Resolution

The bug is resolved in AEM 6.2 and later versions.

If you are on AEM 6.1, then install  AEM 6.1 SP2-Cumulative Fix Pack 14 [1].

[1] https://helpx.adobe.com/experience-manager/release-notes--aem-6-1-cumulative-fix-pack-.html