Backwards compatibility with
J2EE is part of JEE, and it is seen heavily in the EJB3.0 specification.
You're not going to get hammered with J2EE questions on the JEE5 exam, but you will see some questions asking about key differences between the technologies, expecially with EJBs - questions on things such as home interfaces and the ease of creating web services with EJB3 as compared to the previous specification.
-Cameron McKenzie