EJB interview(English)

Q:
What are the different kinds of enterprise beans?

A: Different kind of enterrise beans are Stateless session bean, Stateful session bean, Entity bean, Message-driven bean........... Q:
What is Session Bean?

A: A session bean is a non-persistent object that implements some business logic running on the server. One way to think of a session object........... Q:
What is Entity Bean?

A: The entity bean is used to represent data in the database. It provides an object-oriented interface to ........... Q:
What are the methods of Entity Bean?

A: An entity bean consists of 4 groups of methods, create methods........... Q:
What is the difference between Container-Managed Persistent (CMP) bean and Bean-Managed Persistent(BMP) ?

A: Container-managed persistence (CMP) and bean-managed persistence (BMP). With CMP, the container manages the persistence of the entity bean............ Q:
What are the callback methods in Entity beans?

A: Callback methods allows the container to notify the bean of events in
its life cycle. The callback methods are defined in the javax.ejb.EntityBean interface............ Q:
What is software architecture of EJB?

A: Session and Entity EJBs consist of 4 and 5 parts respectively, a remote interface........... Q:
Can Entity Beans have no create() methods?

A: Yes. In some cases the data is inserted NOT using Java application,........... Q:
What is bean managed transaction?

A: If a developer doesn't want a Container to manage transactions, it's possible to implement all database operations manually........... Q:
What are transaction attributes?

A: The transaction attribute specifies how the Container must manage transactions for a method when a client invokes the method via the enterprise bean’s home or........... Q:
What are transaction isolation levels in EJB?

A: Transaction_read_uncommitted , Transaction_read_committed , Transaction_repeatable_read........... Question: How EJB Invocation happens? Question: Is it possible to share an HttpSession between a JSP and EJB? What happens when I change a value in the HttpSession from inside an EJB? Question: The EJB container implements the EJBHome and EJBObject classes. For every request from a unique client, does the container create a separate instance of the generated EJBHome and EJBObject classes? Question: Can the primary key in the entity bean be a Java primitive type such as int? Question: Can you control when passivation occurs? Question: What is the advantage of using Entity bean for database operations, over directly using JDBC API to do database operations? When would I use one over the other? Question: What is EJB QL? Question: Brief description about local interfaces? Question: What are the special design care that must be taken when you work with local interfaces? Question: What happens if remove( ) is never invoked on a session bean? Question: What is the difference between Message Driven Beans and Stateless Session beans? Question: How can I call one EJB from inside of another EJB? Question: What is an EJB Context? Question: The EJB container implements the EJBHome and EJBObject classes. For every request from a unique client, does the container create a separate instance of the generated EJBHome and EJBObject classes?