Hello, For those of you feeling lost in how to start studying and preparing for the Sun Certified Business Component Developer Exam 5 I think the following will be useful :
First : I suggest have a good knowledge in RMI. Second : Read the first three chapters for the Head First EJB which describes in a very wonderful way the overall architecture of EJB. Third : Download the J2EE 5.0 tutorial. At the end there is an appendix that maps Certification objectives to chapters in this tutorial.
For those new to RMI, In the Head First Design Patters, the chapter that talks about the proxy design pattern, is an excellent explanation of RMI.
I also suggest trying to read tutorials about JNDI, RMI-IIOP to better understand what is EJB is based on.