On Wed, 5 May 1999, Ted Neward wrote:
(other attributions lost)
> >> So I pose this question to my java compatriots with experience in other
> >> realms of server side java. Why would I use an app server or some other
> >> technology? What does EJB give me? Couldn't I use EJB with servlets as
> >> opposed to an EJB centric appserver?
> >
> >In a nutshell (speaking as an "expert" who's read a few dozen more EJB
> >documentation pages than you have :-), EJB is good for centralizing your
> beans
> >on large, high-capacity server(s) that offer the sort of performance,
> >scalability, and reliability you need in an enterprise. The beans live,
> >serverside, in containers that handle a lot of the plumbing issues -- so, for
> >example, the beans can implement the business logic and let the container
> worry
> >about how to connect to databases. You connect to beans from the client side
> >with ordinary RMI calls.
In other words, with servlets, you have to manage the communications
protocol, the server deployment, maintenance, load-balancing, database
hookup, and persistence yourself. In EJB to some extent these are issues
taken care of for you.
For Java client to Java server connectivity, EJB makes it as (almost) easy
as a method call. If you're doing HTML browser to server on the other
hand, it wouldn't be a greater advantage than servlets unless you were
thinking of very high volume services.
> As another "expert" who's working for a company doing a LOT of development
> based on EJBeans, I'd say the above is correct, to a degree. I believe that
> the EJB community isn't quite yet sure what they've created, and are still
> fishing for the patterns they need to do efficient, effective EJB
> development. (My opinion is that EJBs and its
> bean-managed-persistence/container-managed-persistence is fundamentally
> flawed and will be the most highly rewritten part of the EJB spec over time.)
Well speaking from having toiled through G3 and Tuxedo transaction monitor
development in _C_, I can honestly say that the development effort for EJB
is *much* *much* easier. It still has to mature though, agreed.
Unless you are doing enterprise development (the E's there for a reason =)
this probably won't be on your radar screen for a while. But as
e-commerce and EDI heat up on the Internet, you can be sure EJB as it
matures will start to dominate Java server-side development.
. . . Sean, working with EJB and XML and is running out of three-letter words
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