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 and attributes as the real Application
Server, but it is not associated with any node, and does not correspond to any
real server process running on any node.
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
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 Home interface which are not
specific for bean instance, EJB QL.
How can I access EJB
from ASP?
We can use the Java 2 Platform, Enterprise Edition Client Access Services
(J2EETM CAS) COM Bridge 1.0, currently downloadable from Sun
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 provide a local client view. In order to be the target of a
container-managed relationship, an entity bean with container-managed
persistence must provide a local interface.
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 are restricted from performing certain operations: Managing or
synchronizing threads
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, either
because its attributes include values or lists from other tables, or because it
‘owns’ one or more sets of dependent objects. Note that the coarse grained bean
might be mapped to a single table or flat file, but that single table is going
to be pretty ugly, with data copied from other tables, repeated field groups,
columns that are dependent on non-key fields, etc. Fine grained entities are
generally considered a liability in large systems because they will tend to
increase the load on several of the EJB server’s subsystems (there will be more
objects exported through the distribution layer, more objects participating in
transactions, more skeletons in memory, more EJB Objects in memory, etc.)
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.
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 (ends his session). Generally, the session beans implement business
methods (e.g. Bank.transferFunds) that call entity
beans (e.g. Account.deposit, Account.withdraw)
No comments:
Post a Comment