https://docs.oracle.com/cd/E17802_01/j2ee/j2ee/1.4/docs/tutorial-update6/doc/EJBConcepts4.html
You should probably use an entity bean under the following conditions:
- The bean represents a business entity and not a procedure. For example,
CreditCardBeanwould be an entity bean, butCreditCardVerifierBeanwould be a session bean.
- The bean's state must be persistent. If the bean instance terminates or if the Application Server is shut down, the bean's state still exists in persistent storage (a database).
