Hi,
Certification is not imported in your java keys properly. Please follow http://nodsw.com/blog/leeland/2006/12/06-no-more-unable-find-valid-certification-path-requested-targ...
Generally mistake done are While adding a certificate in the url you will append extra space.
No additional configuration needed in aem and also no need to enable https for your functionality.
Many times it is different jre & forking cause issue. Just debug from jre perspective right jre certificate is used Or explicitly configure in startup script to use custom store.
OR
GO to JDK jre/bin folder in command line. In my machine its C:\Program Files\Java\jdk1.7.0_15\jre\bin
C:\Program Files\Java\jdk1.7.0_15\jre\bin>keytool -list -keystore ..\lib\security\cacerts
Enter keystore password: changeit
Above command will list all the certificates available.
Now you can use the following command to import the file into your cacerts keystore.
C:\Program Files\Java\jdk1.7.0_15\jre\bin>keytool -import -alias mycertificate -keystore ..\lib\security\cacerts -file D:\root.cer
Check if certificates are there or not?
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~kautuk
Kautuk Sahni