Frankly that sounds like an awful idea: calling static methods on *business* objects to interact with the databse. Where do I begin in describing what's wrong with this approach.
Firstly: static methods are effectively global so you've made you're entire app dependent on those classes.
Second: You've hard coded your dependency on those classes: you couldn't for example use another object that implements the same interface to substitue: how do you
test? How do you migrate to another environment?
Third: Well third you're using EJBs but then let's just say EJB CMP is an abomination and BMP is worse...
Have look at
Hibernate which is a brilliant ORM library: and in case you're desperate to stick with EJB (some kind of masochist huh?) then a) you can use Hibernate from Stateless Session beans and b) Gavin King, the lead dev for Hibernate, is also on the EJB 3.0 CMP committe and reports EJB 3.0 CMP will look an awful lot like Hibernate.
Edward
If JavaRanch had sigs mine would say: Burn EJB and their creators!