What is better approach for web site, to use Hibernate inside servlets or to use Hibernate inside session EJB? Is there one important reason why something should be done or is there some serious performance problem?

What is better to go shopping, a buggy or a truck? Please specify "website".

Web site will be build around RDBMS, no static pages, with security, roles, about 30000 "transaction" per month.

Do you know what EJB is? Do you know what Servlets are? It's certainly better to decide for an architecture based on these questions, rather than only on Hibernate. Hibernate is flexible in any environment.

I am familiar with EJB and only wrote hello world in servlet, client was plain Java Swing application. So far, I didn't use any Object-Relational mapping tool and it sounds like with Hibernate you can have functionality in servlet like you have with EJBs. Another issue is application server itself.

My view on the whole thing:

- Session EJBs is a means to make resusable application logic that can be called through a network. That's the holy grail of software resue, sort of - f.eg, design a method that returns a list of all customers, and place it in a (session) EJB on a server. In the future, whenever you need to retrieve a list of all customers, just call that method on that server, be it from a SWING GUI, another application server, a handheld device, etc. Is one of your app servers "getting full"? No problem - just add another server in the network and continue. Reusability, reusability, reusability.

- I look at Hibernate as a way to achieve DBMS independence that would be hard to achieve if I had to code the SQL manually. All my application logic is implemented as SLSB (Stateless Session Beans) methods, and can be seen as DBMS independent stored procedures, really. Does customer X run Oracle? No problem - just set the Hibernate dialect to Oracle. Does he/she run DB2? SQLServer? Postgres? Change one line in the config, and you're done. THAT's the strength of Hibernate. Oh, and it's 100000 times easier to use and much, much, more performant that CMP Entity Beans (the only alternative if you want the same functionality).

In short: if you don't mind having to recode the application logic as soon as you add a new UI, go for servlet-only. On the other hand, if you think it's possible that you in the future may need to add interfaces for "thick clients" or handhelds (or think that you could have use for that fancy dooFoo() method in some other app), go for SLSB Session Beans.

My

I do not think it is meaningfull to use SLSB for future, it will be "evil legacy" in the futures buzz words, do solution for today and refactor it later.

There is one more thing, you should split user interface and business logic, which mean that you can use servlets and EJBs for business logic and we are again on beginning.... :-)[/quote]

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And how are you planning to use the business logic implemented in servlets from a Swing GUI..? Using SOAP? Of course, that's one way..but different SOAP implementations vary, so I wouldn't trust that technique yet..

Logic is one thing, presentation is another - that's why I go for SLSBs for the logic part.

And how are you planning to use the business logic implemented in servlets from a Swing GUI..? Using SOAP? Of course, that's one way..but different SOAP implementations vary, so I wouldn't trust that technique yet..

Logic is one thing, presentation is another - that's why I go for SLSBs for the logic part.[/quote]

Hi all,
I agree with carnitz,
logic part = SLSBs for J2EE
for standart web app. U do not need SB.

one ? more. Wenn I call SLSB throw servlet to jsp it`s going fine,
but wenn I have client which call SLSB`s I take some strange
result.
Wenn I call any primitive type like int,String etc. it`s working good.
Wenn I call hibernate object then come exception no Session exist.

Guys, How do you hold object in user session???
How do U hold hibernate collection in session???

This sounds like a lazy loading exception, which implies that you haven't grasped the concept of lazy loading. Either set lazy="false" for your collections of child objects, or make a separate initialization every time you need access to a child. (Hope I make sense here)

Read the docs for more info.

- Mikael