Category: J2EE Category

Entity Beans actually represents the data in a database. It is not that Entity Beans replaces JDBC API. There are two types of Entity Beans Container Managed and Bean Mananged. In Container Managed Entity...

The developer, according to the specification, cannot directly control when passivation occurs. Although for Stateful Session Beans, the container cannot passivate an instance that is inside a transaction. So using transactions can be a...

The primary key can’t be a primitive type–use the primitive wrapper classes, instead. For example, you can use java.lang.Integer as the primary key class, but not int (it has to be a class, not...

Step 1: Retrieve Home Object reference from Naming Service via JNDI. step 2: Return Home Object reference to the client. step 3: Create me a new EJB Object through Home Object interface. step 4:...

You can pass the HttpSession as parameter to an EJB method, only if all objects in session are serializable. This has to be consider as “passed-by-value”, that means that it’s read-only in the EJB....

The EJB container maintains an instance pool. The container uses these instances for the EJB Home reference irrespective of the client request. While refering the EJB Object classes the container creates a separate instance...

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 called EntityContext. Session beans use a subclass...

EJBs can be clients of other EJBs. It just works. Use JNDI to locate the Home Interface of the other bean, then acquire an instance reference, and so forth.

In several ways, the dynamic creation and allocation of message-driven bean instances mimics the behavior of stateless session EJB instances, which exist only for the duration of a particular method call. However, message-driven beans...

In case of a stateless session bean it may not matter if we call or not as in both cases nothing is done. The number of beans in cache is managed by the container....