If you have WAS 8.5.5 and your application is not starting due to major minor version of class files errors on starting, you might be facing the JDK problem.
Websphere 8.5.5. is shipped with 1.6 JDK version( which is vague) but your application might have compiled code in recent version of Java.
So in this case your option is to upgrade to 8.5.5.11 where 1.7.1 and JDK 8 are supported.
