Hi!
Which version of the EJB certification?
I have written an electronic book (distributed as a PDF) that can be used as part of the material when preparing the EJB 6 (JPA not included) certification.
It seems some people have used this book when preparing for the EJB 5 certification too, studying some of the examples included.
Follow the link in my signature, register on Slideshare and download it for free if you are interested.
Best wishes!