AEM 6.1 Downgrade of a Java version and QuickStart shows UnsupportedClassVersionError major.minor version 52.0

Sometimes we get below error when accessing any AEM pages.

Caused by: java.lang.UnsupportedClassVersionError: org/apache/jsp/apps/sling/servlet/errorhandler/_404_jsp : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)

Resolution:
NOTE: Please backup your AEM instance before doing this

• Go to http://localhost:4502/system/console/configMgr
• If the page opens, login as "admin"
• Go to Menu > OSGI > Bundles [http://localhost:4502/system/console/bundles]
• Find this "Apache Sling Commons FileSystem ClassLoader (org.apache.sling.commons.fsclassloader)" and note the BundleID (it is 218 for me)
• STOP AEM
• On Windows Explorer go to this path where your AEM is installed.. $path\aem-61-author\crx-quickstart\launchpad\felix\bundle218\data
• Delete the classes folder under it.
• Restart AEM.. this should fix the issue.

If the page above does not open,

• (assuming the bundle-id is 218)STOP AEM
• On Windows Explorer go to this path where your AEM is installed.. __ $path\aem-61-author\crx-quickstart\launchpad\felix\bundle218\data __
• Delete the classes folder under it.
• Restart AEM.. this should fix the issue.