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) 

Resoultion:

NOTE: Please backup your AEM instance before doing this

• Go to 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.