[J2EE Base EJB Programming] SessionBean - "Hello World" using a SessionBean[2/]

        In the previous lesson, you have already implmented EJB using a SessionBean. Actually, there are three kinds of EJB; SessionBean, EntityBean and MessageDrivenBean. Rather than talking about all specifiactions of these three EJB, let's focus on a SessionBean; especially, a "stateless" SessionBean. What are the "stateless" means? Never mind. Forget about it. Just try to control yourself to imaginate there is only one kind of EJB; stateless SessionBean. It will helpful to understand what EJB is. Hereafter, EJB means a stateless SessionBean until I wake you up.
        To deploy EJB, you have to do some secrete rite; Building EJB and Deploying EJB to weblogic. You may think it is just copying .class files from local location to weblogic server. Therefore, there is no need of difficult process of deploy; it's not true. Complicated deploy process of EJB is directly related to its signification of existance; make programming business logic easy with complicated deploy process rather than make programming business logic difficult with simple deploy process.
        Whether you know what is B/L(Business Logic) or not, programming B/L is different from general logic; it should contain transaction control, security management, and so on. Can you do these things? I can't. Eventhough you are willing to do those things, it takes too much time and endeavor. Moreover, it makes too many errors to maintain it because not all programmers are competent as you. Even a novice programmer can make B/L if he obeys the specifications of EJB. This is why the specifications of EJB are strict and long. Don't be confused between the complexity of the EJB specfication and the complexity of the EJB programming; the complexity of the EJB specification is high and the complexity of the EJB programming is low, not the opposite. In other words, programming EJB is easy if you obey the complex specifications of EJB.

        In my opinion, the complexity of specifications as higher as possible, the compexity of programming is lower. Actually, you have already made a "Hello World" EJB without any understaing about what is EJB. Therefore, understanding the specification of EJB is the most important thing when you start to use EJB. If you agree, follow me. See you.


by 해적 | 2007/07/18 14:40 | LessonNotes | 트랙백 | 핑백(2) | 덧글(0)

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Linked at Treasure iLand :.. at 2007/07/18 14:41

... touched too many things without enough explanations. Let's see how these work, next time. &lt;NEXT&gt; ... more

Linked at Treasure iLand :.. at 2007/07/18 17:37

... tmp &lt;PREV&gt; ... more

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