RE: [Springframework-developer] EJBs vs POJOs

[James C. <dja...@gm...>]

Spring simply provides a convenient fa=E7ade to other persistence
implementations, including EJB!

You may have meant Entity Beans when you stated EJB. If so, another
way of wording your question is, "Are there cases when EJB is
preferred as a persistence mechanism over a POJO persistence
(Hibernate, TopLink, iBatis, JDO, EJB3, and dozens of others)
mechanism?"

Take these with a grain of salt, since I don't have hands-on
experience with all of the POJO persistence mechanisms. A few benefits
don't come easily to the world of POJO persistence.

a) POJO-based approaches (AFAIK) with the exception of EJB3, do not
support distributed security contexts. Even if you were writing an EJB
implementation, you would want to limit the number of network calls
your app has to make. But if you really have part of your application
on one machine, and part on another, you can invoke EJB's on the
various machines and remain within the same security context.

b) Clustered sessions are still the realm of the J2EE container.
Distributed caching of persistent object between machines is difficult
to achieve using POJO persistence.

c) Support for CORBA clients is a standard feature of J2EE.

There may be more. Of course, EJB3 will probably turn this discussion
on its ear.

If I totally missed your point, and you just wanted to know if Spring
provided lightweight (sorry Hani) alternatives for the specification
components that make up Enterprise Java Beans (EJB), namely:

- Stateless Session Bean (yes, via service interfaces, pojos you write)
- Stateful Session Bean (no)
- Entity Bean (yes, via Hibernate, TopLink, iBatis, JDO passthrus)
- Message Driven Bean (No, AFAIK)
- Timer Bean (yes, via quartz)
- Web Service Endpoints (yes, via http invoker, hessian, burlap, axis, mayb=
e
others)




> -----Original Message-----
> From: spr...@li...
> [mailto:spr...@li...] On=20
> Behalf Of Garvey, Paul M (GE Commercial Finance)
> Sent: Thursday, April 21, 2005 3:53 PM
> To: spr...@li...
> Subject: [Springframework-developer] EJBs vs POJOs
>=20
> All,
>=20
> I fairly new to Spring and I am currently reading some documentation=20
> on it. I have bought into the concept of the lightweight feature of=20
> Spring. I do have a quick question, Springs seems to handle every=20
> scenario that I would
> use EJBs, is there a few cases where EJBs are unavoidable to use? In othe=
r
> words
> are there any scenarios where Spring is just not the best tool to use and
> EJBs is
> the more suited? Any thoughts?
>=20
> Paul
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
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