We have faced several issues which customers in a non certified platforms where after a long time and huge troubleshooting efforts we concluded that the issue was fixed after moving to a tested configuration. WebLogic Server might run in any other non certified platform like any flavor of Linux, but we can not assure that it will work correctly.
So, What if you have a problem when running a non certified configuration? If you don't find a known issue in the net or in My Oracle Support, try to reproducing the issue in a certified configuration. That will save a lot of time because as per out experience, the most probably cause of the issue is that the configuration where you are running WebLogic Server is causing the issue.
Eventually, if the issue still occurs, that will help to focus on the real issue and not in the noise added by the environment used to run WebLogic server. It is also recommended to be in the latest JDK, that will help you to include in your environment the latest security fixes and patches for known issues already faced by other customers. Another thing to consider is that you are upgrading your WebLogic Server. Then, you will probably need to upgrade your JDK as well. Always check certification matrix. Here you can find the supported configurations of Fusion Middleware products.
If you are in 12.1.1 or 12.1.2, make sure you pick the correct link. WebLogic Server 12.1.2 is very different from 12.1.1. If you are in 11g, you will need to pick the document depending on your configuration.
For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center.