Based on the Enterprise JavaBeans (EJB) specification, Enterprise JavaBeans are Java components that typically implement the business logic of Java Enterprise Edition (JEE) applications as well as data access.
There are basically three types of Enterprise JavaBeans:
Stateless Session Beans (SLSB): SLSB are objects whose instances have no conversational state. This means that all these bean instances are equivalent when they are not servicing a client.
Stateful Session Beans (SFSB): SFSB support conversational services with tightly coupled clients. A stateful session bean accomplishes a task for a particular client. It maintains the state for the duration of a client session. After session completion, the state is not retained.
Message-driven beans (MDB): MDB are a kind of Enterprise Bean that are able to asynchronously process messages sent by any JMS producer. (We will discuss MDB in Chapter 7, Adding Java Message Service to Your Applications.)
Besides standard EJB...