It is important to know which WebLogic versions and JDK versions are supported with Oracle Entitlement Server. If you would like to see the Certification matrix for OES, here it is. Only WebLogic 10.3.0 is supported for Admin and SSM, if you are using WebLogic Portal, 10.2.0 is supported.
From my experience, WebLogic 10.3.1 is also supported by Admin and SSMs. But one should be very careful while using JDK versions while installing. I have tested JDK 6 for Admin Server and SSM while installing and it works fine. Incase you are protecting a WebLogic domain using WebLogic SSM, you would specify the JDK version while creating the domain using config wizard. It is better to use JDK 5 instead of 6. Follow the same for WebLogic Portal as JDK 5 while creating domain.
I have seen weird errors in the scenario where WebLogic Portal is being protected by OES. I created the WebLogic Portal domain with JDK6 and tried to create the SSM instance using ConfigTool. The ConfigTool stopped after the below message is shown in the response.
Checking if default ARME port is free: 8014
Generating policy files based on templates …
Checking if SSM instance already present
Checking to see if SSM ARME port is free.
Checking JDBC parameters…
Checking to see if asipassword was run…
Assuming Domain is Weblogic 9.x and above
Checking WLS version number…
Checking to see if weblogic server is running
Weblogic server not running
Checking to see if weblogic server starts (This may take several min. depending on the host) logging into weblogic server.
The solution is to create the domain using JDK 5 version.