Figure 2.2. The ActionBazaar scenario implemented using EJB 3. From the EJB 3 perspective, the presentation
layer is an amorphous blob that generates business logic-tier requests (in this case it's implemented using JSF).
The business logic-tier components match up with the distinct processes in the scenario—putting a bid on an item
and ordering the item won. The business logic-tier components use JPA entities to persist the application state into
the database via persistence-layer DAO components.