EJB interview questions
- what are Container-Managed Transactional attributes ? view answer
- What's difference between httpsession and EJB session bean ? view answer
- What are the Differences between EJB 3.0 and EJB 2.1? view answer
- Q. what are Container-Managed Transactional arributes ? view answer
- What is the default transaction attribute for an EJB? view answer
- Difference between SessionBean remove() and EntityBean remove() method? view answer
- Why do we have a remove method in both EJBHome and EJBObject? view answer
- 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? view answer
- What is the difference between a ?Coarse Grained? Entity Bean and a ?Fine Grained? Entity Bean? view answer
- What are the Interfaces need to create to implement Session Bean with Exmaple? view answer
- What are the parameters must follow for Session Bean ? view answer
- What are the callbacks method in Session Bean ? view answer
- What are the ways for a client application to get an EJB object?
- What is handle and why it is used in EJB? view answer
- What is an EJB Context? view answer
- Implement Local and Remote Interfaces in EJB? view answer
- How can I call one EJB from inside of another EJB?
- What is the difference between Message Driven Beans and Stateless Session beans? view answer
- What happens if remove( ) is never invoked on a session bean? view answer
- Can you control when passivation occurs?
- Can the primary key in the entity bean be a Java primitive type such as int?
- 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?
- How can i maintain a user session between servlets and stateful session ejbs? view answer
- What's difference between Servlet/JSP session and EJB session view answer
- 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?
- How to call any EJB from a servlet/JSP/Java Client? view answer
- What are transaction isolation levels in EJB?
- What are transaction attributes?
- What is bean managed transaction?
- Can Entity Beans have no create() methods?
- What are the callback methods in Entity beans?
- What is the difference between Container-Managed Persistent (CMP) bean and Bean-Managed Persistent(BMP) ?
- What are the methods of Entity Bean?
- What is Entity Bean?
- What is Session Bean?
- What are the different kinds of enterprise beans?
!!! EJB interview questions !!!
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 is as a logical extension of the client program that runs on the server.
Session beans are used to manage the interactions of entity and other session beans,access resources, and generally perform tasks on behalf of the client.
There are two basic kinds of session bean: stateless and stateful.
Stateless session beans are made up of business methods that behave like procedures; they operate only on the arguments passed to them when they are invoked. Stateless beans are called stateless because they are transient; they do not maintain business state between method invocations.Each invocation of a stateless business method is independent from previous invocations. Because stateless session beans are stateless, they are easier for the EJB container to manage, so they tend to process requests faster and use less resources.
Stateful session beans encapsulate business logic and state specific to a client. Stateful beans are called "stateful" because they do maintain business state between method invocations, held in memory and not persistent. Unlike stateless session beans, clients do not share stateful beans. When a client creates a stateful bean, that bean instance is dedicated to service only that client. This makes it possible to maintain conversational state, which is business state that can be shared by methods in the same stateful bean.