EJB

Question 1

EJB

Answer 1

Enterprise Java Beans

• one of the several Java APIs for standard manufacture of enterprise software
• a server-side software element that summarizes the business logic of an application
• we need an application server (EJB container) such as Jboss, Glassfish, Weblogic, Websphere, etc. to run the EJB application.
• If you need a component that accesses the database or is accessed from multiple clients

Question 2

JavaBean

Answer 2

A type of java class that encapsulates many objects into a single object (the bean)

It follows certain standards:

1. it should be Serializable (must implement Serializable)
2. it should have a (public) no-arg constructor
3. All properties must be private with public getter and setter methods

Question 3

There are 3 types of EJB

Answer 3

• Session Bean
• Entity Bean
• Message Drive Bean

Question 4

Session Bean

Answer 4

• It stores data of a particular user for a single session. It gets destroyed as soon as the user session terminates.
• It contains business logic that can be invoked by local, remote, or web service clients.
• when a client wants to use an application distributed on a server

Question 5

Entity Bean

Answer 5

• it represents persistent data storage. user data can be saved to the database via entity beans and later on be retrieved from the database.
• it is deprecated and now replaced with JPA (Java Persistent API).

Question 6

SessionBean Interface

Answer 6

it defines methods that the EJB container uses to notify a session bean instance of the instance’s life cycle events