Re: Enterprise Java -- JAVA400-L

With the release of EJB 3.0, EJB programming has been greatly simplified. Now it may be a better alternative to Spring + Hibernate etc.

Cite from a recent book (EJB 3.0 in Action):

"Although many people think EJBs are overkill for developing relatively simple web applications of moderate size, nothing could be further from the truth. When you build a house, you don't build everything from scratch. Instead, you buy materials or even the services of a contractor as you need it. It isn't too practical to build an enterprise application from scratch either. Most server-side applications have a lot in common, including churning business logic, managing application state, storing and retrieving information from a relational database, managing transactions, implementing security, performing asynchronous processing, integrating
systems, and so on.
As a framework, the EJB container provides these kinds of common functionality as out-of-the-box /services /so that your EJB components can use them in your applications without reinventing the wheel. For instance, let's say that when you built the credit card module in your web application, you wrote a lot of complex and error-prone code to manage transactions and security access control. You could have avoided that by using the declarative transaction and security services
provided by the EJB container. These services, as well as many others you'll learn about in section 1.3, are available to the EJB components when they are deployed in the EJB container, as you can see in figure 1.2. This means writing high-quality,
feature-rich applications much faster than you might think. The container provides the services to the EJB components in a rather elegant new way:"

Regards,

Walden H. Leverich wrote:

If you aren't doing that or don't have multiple servers then not much is being gained outside of a good amount of EJB

complexity.
Walden's rule of EJBs... You don't need them unless you know enough to
know you need them. NO ONE should start out using EJBs. If you're not
sure (and I mean damn sure) what they are, and why they're a benefit
then you don't know enough to use them (and probably don't need them).

BTW, I'm not trying to be a jerk, I'm the first to admit, I don't know
enough to use them, but from what I've seen, there's seldom, if ever, a
need to use them in the systems we run on iSeries machines. Running a
trading floor? Perhaps... Designing FirstData's credit-card clearing
core? Probably... Doing anything we all do, nope.

Aaron is right, they're loved in multi-server, multi-consumer
environments. And "multi" doesn't mean a primary LPAR and a secondary
box, we're probably talking dozens of servers before they really
shine... At which point, they really shine.

-Walden