i found on below link that Oracle JRE8 is not supported with Adobe CQ 5.6 version.
Please describe which type of issue can face as i am using JRE8 update 65 from last 20 days and till now didn't found any issue
https://docs.adobe.com/docs/en/cq/5-6/deploying/technical_requirements.html
Regards
Rajnish Jha