What is an EJB Context?
EJBContext is an interface that is implemented by the container, and it is also a part of the bean-container contract. Entity beans use a subclass of EJBContext... Read more »
‘EJB Interview Questions’ - KyaPoocha.com
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 by writing the appropriate JDBC code.... Read more »
What is the need of Remote and Home interface. Why cant it be in one?
The main reason is because there is a clear division of roles and responsabilities between the two interfaces. The home interface is your way to communicate with... Read more »
Can I develop an Entity Bean without implementing the create() method in the home interface?
As per the specifications, there can be ‘ZERO’ or ‘MORE’ create() methods defined in an Entity Bean. In cases where create() method is not provided, the... Read more »
Static variables in EJB should not be relied upon as they may break in clusters.Why?
Static variables are only ok if they are final. If they are not final, they will break the cluster. What that means is that if you cluster your application server... Read more »
When should I adopt BMP and when I should use CMP?
You can use CMP and BMP beans in the same application… obviously, a bean can be BMP or CMP, not both at the same time (they are mutually exclusive). There is a... Read more »
What are the callback methods in Entity beans?
The bean class defines create methods that match methods in the home interface and business methods that match methods in the remote interface. The bean class also... Read more »
What is software architecture of EJB?
Session and Entity EJBs consist of 4 and 5 parts respetively: 1. A remote interface (a client interacts with it), 2. A home interface (used for creating objects... Read more »
Can Entity Beans have no create() methods?
Yes. In some cases the data is inserted NOT using Java application, so you may only need to retrieve the information, perform its processing, but not create your... Read more »
What are transaction isolation levels in EJB?
1. Transaction_read_uncommitted- Allows a method to read uncommitted data from a DB(fast but not wise). 2. Transaction_read_committed- Guarantees that the data you... Read more »
What are Local Interfaces? Describe.
EJB was originally designed around remote invocation using the Java Remote Method Invocation (RMI) mechanism, and later extended to support to standard CORBA transport... Read more »
Is it legal to have static initializer blocks in EJB?
Although technically it is legal, static initializer blocks are used to execute some piece of code before executing any constructor or method while instantiating... Read more »
What is the difference between session and entity beans?
An entity bean represents persistent global data from the database; a session bean represents transient user-specific data that will die when the user disconnects... Read more »
What is EJBDoclet?
EJBDoclet is an open source JavaDoc doclet that generates a lot of the EJB related source files from custom JavaDoc comments tags embedded in the EJB source file. Read more »
What is the difference between a Coarse Grained Entity Bean and a Fine Grained Entity Bean?
A ‘fine grained’ entity bean is directly mapped to one relational table, in third normal form. A ‘coarse grained’ entity bean is larger and more complex,... Read more »
Are enterprise beans allowed to use Thread.sleep()?
Enterprise beans make use of the services provided by the EJB container, such as life-cycle management. To avoid conflicts with these services, enterprise beans... Read more »
What is the relationship between local interfaces and container-managed relationships?
Entity beans that have container-managed relationships with other entity beans, must be accessed in the same local scope as those related beans, and therefore typically... Read more »
What’s new in the EJB 2.0 specification?
Following are some of the main features supported in EJB 2.0: 1. Integration of EJB with JMS, 2. Message Driven Beans, 3. Implement additional Business methods in... Read more »
What is the new basic requirement for a CMP entity bean class in 2.0 from that of ejb 1.1?
It must be abstract class. The container extends it and implements methods which are required for managing the relationships Read more »
What is a Server Group?
A server group is a template of an Application Server(and its contents) i.e, it is a logical representation of the application server. It has the same structure... Read more »