Hi Guys,
This issue occurred when I did migration from one environment to another hope it would also helpful to someone facing same issue. This issue could also happen if someone deletes the group or users used in Oracle Entitlement Server(OES) policies.
After migration once you try to access OES admin console(apm) and search for authorization policies you would see a popup “java nullpointer exception” . The root cause of this problem is all dependent user’s or groups referred in the OES policies under principals is not present in the identity store.If you are using weblogic user store then create the required user and groups in the weblogic embedded ldap and try to access.
Cheers.