Enterprise Java Beans or EJB is a part of the JAVE EE API. To create an EJB, a Java class should import the following libraries:
import java.rmi.RemoteException; import javax.ejb.*;
The concept of EJB is to standardize persistence, transaction and security in the back-end side of enterprise applications.
1. Stateless EJB – This is used for single method or single transaction only
2. Statefull EJB – Used for a full process transaction and the client should keep track of the state of the transaction. An example Bean would be a Bank Account and it’s states would be: Withdraw, Deposit, Close Account.
3. Message Driven Beans – an EJB triggered by a an external message, not from a method call
simple EJB example: