EJB views

What is Remote client view in EJB 2.0?

The remote client view is location independent of a bean.

A client running as a bean instance in the same JVM uses the same API to access the bean as another client running in a different JVM on the same or different machine.

It provides the location transparency.

What is Local client view in EJB 2.0?

Unlike the remote client view, the local client view is location dependent of a bean.

To access an enterprise bean by local client view, it is required both the remote client and the enterprise bean which provides the view of local client view in the same JVM.

Thus, the Local Client View does not provide location transparency provided by the remote client view.

What is the difference between ejbCreate() and ejbPostCreate()?

Only ejbCreate() is available to Session Bean and Message Driven Bean.
Both ejbCreate() and ejbPostCreate() are available for Entity Bean.

ejbPostCreate() returns void and has the same parameters as that of ejbCreate(). To set a relationship field to initialize the bean instance, ejbPostCreate() is used and is not supported in the ejbCreate() method.

Any post-create processing is needed before serving the client request, the ejbPostCreate( ) method allows this designated process.

What is the difference between find and select methods in EJB?

select() method:

1. A persistent field of a related entity bean is returned by select() method. It is defined in Entity Bean class.
2. A select() method can not be invoked by a client, because the method is not exposed in local or remote interfaces.
3. It can only be invoked by the methods that are within the Entity Bean class.

finder() method:

1. A finder method can retrieve multiple entity beans for the storage persistence.
2. A finder method can return only a local or remote interface or a collection of interfaces.
3. A finder method is defined in the Entity Bean class for Bean-Managed Persistence and not defined in the Container-Managed Persistence.