> Also, are EJBs really "Write Once, Run Anywhere"? I have heard stories > that it doesn't do that... The two articles from the techmetrix website > does not seem to think it does. Nope. But the fact that you can learn EJB once and program for any server, and move code between server with reasonable modifications, is a boon. I think EJB portability is more about developer and expertise than about code. If you compare EJB to the current state of application servers, where your code is 100% non portable and you need to relearn the API when you change products (or try to integrate them), then you'll see the benefit of EJB. > The fact that EJB restricts loading native libraries (I interpret it as > prohibit JNI calls) makes reuse of existing components impossible if the > implementation of the component is not implemented in Java (which IMHO, > is the majority of the case). The spec did not mention of any other way > to allow such software reuse. Now we could wrap these components with a > normal Java class (not an EJB), and have EJB import these classes, but > inherently, this is really no different from issuing JNI calls within > EJB itself. Or am I interpreting this all wrong? It does not prohibit you, e.g. from using a library that might access JNI or spawn it's own thread. JDBC, JMS and even JNDI are prime examples of that. But they they have been properly designed to provide their own level of reliability, security, monitoring, etc so you can trust them to work well in a demanding environment. EJB relieves you of the need to care about reliability, security and scalability when you write beans, all these is simplified and abstracted, but in return you have to promise not to violate the design that gives you all that. > Also, if EJB prohibit synchronizing threads, how would it adress the > typical producer/consumer problem which is quite a common scenario in > server requirements/designs? There is no producer/consumer in the EJB world, this sort of functionality either leaves on the client or inside the resources that the EJB bean accesses. Typically if your business logic is about being produced/consumed you will be looking at JMS. I think what we need are good real world scenarios so people can see how different design patterns are being used and reflect that on their projects. arkin > Lastly, I'm curious on how the container classes is designed, > generically enough to meet everyone's need and flexible enough for > people to customize??? And if the container classes do allow > customization, how can it guarantee the EJB components can WORA? Where > would I find the spec/guidelines for that? > > Thank you very much for your responses... > > Manomohan Kalathil wrote: > > > > Visit www.techmetrix.com for a study of a few of these appservers > > > > Mano > > > > |Subject: Application Server - Feedback > > | > > | > > |Hello, > > | Following is a list of app servers that I am currently evaluating. > > | > > | WebLogic > > | Secant > > | Novera ( I would like to but no download is available :( ) > > | WebSphere > > | NetDynamics ( but SUN recently announce their new product > > |availability > > | in early next year - alliance with Netscape - On hold ) > > | Oracle > > | > > | > > | > > | > > | If anybody has experince on these products would you please send me > > | their feedbacks on these products. > > | > > | I am looking at the following features. > > | > > | 1. Scalability > > | 2. Fault tolerence > > | 3. Maintanability > > | 4. Transaction Mgmt - Anybody supports nested and distributed > > |transactions > > | 5. Application Partioning > > | 6. EJB1.1 support > > | 7. IDE integration > > | 8. Integration with bean providers like Theory center - not > > |anymore ( WebLogic > > | got them, I think ) > > | > > | 9. Easy to use and minimal configuration > > | 10. Mem/Space reqmts. > > | 11. Database Independence > > | > > | Any help is really appreciated - Especially if anybody has > > |done a thorough study on any > > |of these app servers and would like to share your experince will > > |be a great help. > > | > > | > > | -Thx > > | -Reji > > | > > -- > Yiwen Jiang > CRYPTOCard > [EMAIL PROTECTED] > Tel: (613) 599-2441 x245 > Fax: (613) 599-2442 > > =========================================================================== > To unsubscribe, send email to [EMAIL PROTECTED] and include in the body > of the message "signoff EJB-INTEREST". For general help, send email to > [EMAIL PROTECTED] and include in the body of the message "help". -- ____________________________________________________________ Assaf Arkin [EMAIL PROTECTED] CTO http://www.exoffice.com Exoffice, The ExoLab Company tel: (650) 259-9796
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