If we define the entity bean as being reentrant, multiple clients can connect to the Entity bean & execute methods within the entity bean concurrently. Container... Read more »
For a Session bean - one EJB object for one bean instance. For entity bean - it depends , if 2 users are accessing one row at time then one EJB object is used for... Read more »
Deployment descriptor is a XML file.which is used to locate the web application by container.it includes the details of respective bean. Read more »
Container services are totally depends upon the “vendor implementation”. But more or less most of the vendors suppots the basic services like, LifeCycle Management... Read more »
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. Read more »
An MDB is essentially a message consumer that can listen to a message destination or a message endpoint and gets activated when a message arrives. By design, MDBs... Read more »
An EJB can use local client view only if it is really guaranteed that other enterprise beans or clients will only address the bean within a single JVM. With local... Read more »
Abstract schema is part of an entity bean’s deployment descriptor which defines the bean’s persistent fields and their relationship. Abstract schema is specifed... Read more »
A Java Bean is a software component written in the Java programming language that conforms to the JavaBeans component specification. The JavaBeans APIs became part... Read more »
A select method can return a persistent field (or a collection thereof) of a related entity bean. A finder method can return only a local or remote interface (or... Read more »
The following code snippet shows how a servlet instantiates a bean and initializes it with FORM data posted by a browser. The bean is then placed into the request,... Read more »
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... Read more »
Retrieve Home Object reference from Naming Service via JNDI. Return Home Object reference to the client. Create me a new EJB Object through Home Object interface.... Read more »
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... Read more »
Stateless session bean- An instance of these non-persistent EJBs provides a service without storing an interaction or conversation state between methods. Any instance... Read more »
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... Read more »
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... Read more »
EJB QL is a Query Language provided for navigation across a network of enterprise beans and dependent objects defined by means of container managed persistence.... Read more »
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. In... Read more »
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. Read more »