EJB interview questions

1. What are the different kinds of enterprise beans? - Different kind of enterrise beans are Stateless session bean, Stateful session bean, Entity bean, Message-driven bean.
2. What is Session Bean? - 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.
3. What is Entity Bean? - The entity bean is used to represent data in the database. It provides an object-oriented interface to ____.
4. What are the methods of Entity Bean? - An entity bean consists of 4 groups of methods, create methods.
5. What is the difference between Container-Managed Persistent (CMP) bean and Bean-Managed Persistent(BMP) ? - Container-managed persistence (CMP) and bean-managed persistence (BMP). With CMP, the container manages the persistence of the entity bean.
6. What are the callback methods in Entity beans? - 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.
7. What is software architecture of EJB? - Session and Entity EJBs consist of 4 and 5 parts respectively, a remote interface.
8. Can Entity Beans have no create() methods? - Yes. In some cases the data is inserted NOT using Java application,.
9. What is bean managed transaction? - If a developer doesn’t want a Container to manage transactions, it’s possible to implement all database operations manually.
10. What are transaction attributes? - 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.
11. What are transaction isolation levels in EJB? - Transaction_read_uncommitted, Transaction_read_committed, Transaction_repeatable_read.

Posted in: Java