org.apache.openejb.beancontext can not accsess a member of any class with private field on tomee8

Question

Using java 8. I upgraded tomEE7 to tomEE8 plus. Using ojdbc6 for oracle db. I added ojdbc6.jar and bval-core.jar to the tomEE lib directory.

Then when the app started to run, in the middle of deployment (before it began to run my code) i received an error of:

java.lang.IllegalAccessError error:
class org.apache.openejb.beancontext can not accsess a member of class "some name class of mine" with modifiers private .

I have some private fields in that class. I added getters and setters but it didn't help.

On tomEE7 it worked fine.

only when upgrading to tomEE8 plus it started to happen.

Any clue to why it may happen, what to check or any advice would help.