Is developping an EJB application is considered like a web services ?
Or the two are different ?
Or you can make EJBs like web services ?
A:
An EJB is an object that has some useful methods, typically Business Logic, and those methods can be invoked by clients in a number of ways - one of those ways can be a Web Service interface.
In development terms it's pretty much just a matter of annotating the EJB with your chosen interfaces style.
Putting the logic in an EJB can be a good idea because you get easy control over Transactional behaviour, declarative Security and scalability from the EJB container.
djna
2010-09-22 10:57:48
+2
A:
My answer would be yes and no.
No in the sense that EJB is a programming model. This programming model contains concepts such as security, transaction demarcation, state management and persistency (stateful or stateless beans), and more. While web service is more a remoting technology, that is, a way to connect systems, which is SOAP in the case of web service. Under this perspective both are completely different topic (Web service could be compared to RMI-IIOP though).
Yes in the sense that both are usually referred as technologies to expose a service to the outside (as long as it's stateless). Under this perspective they belong to the same category. And an EJB can indeed be exposed very easily as a web service by annotating the bean accordingly.
Hope it brings some light to the distinction.
ewernli
2010-09-22 20:50:09
I did understand your "yes", but not your "no". Can you tell me more the differences between "remoting technology" and "programming model". because to me, they seem the same.
mohamida
2010-09-23 08:21:08
You design a solution so that it matches/leverages a programming model (examples: EJB, ASP.NET, Servlets, CORBA, maybe even MapReduce, etc.) A remoting technology is just a standard to exchange/marshal data (examples: SOAP, RMI, IIOP, JSON, etc.). The term web service is actually vague and can be seen as a bit of both.
ewernli
2010-09-23 10:34:39