Hi Sawalia, I can see two main reasons for using EJB and not CORBA, one on the business/commercial side and the other on the technical side. Commercially the Java middleware industry has adopted this technology, and practically all application servers are EJB compliant. Even ORB vendors like IONA and InPrise are moving into this space. EJB servers will provide you with capabilities that are not defined by the spec and are left for the implementation. These include load balancing, fault tolerance, sophisticated management tools, smart caching, thread and connection pool management and integration with excellent persistence solutions (OODBs and O/Rs), etc. It seems like there is a clear trend towards EJB, and if you bet on EJB you'll find yourself with better options (short term already and definitely long term). We definitely see that with our customers, which are looking for EJB support. On the technical side, there can be many arguments why the EJB and Enterprise Java programming models are better. The most obvious one in my mind is EJB's concept of deployment descriptors and declarative specification of components properties. It allows you to support global (distributed) transactions in your components with no programming. This is definitely much more powerful then programming OTS directly. Same applies for other properties such as security. I also really like JMS (publish/subscribe messaging service), which is supported by EJB servers such as WebLogic, and by independent messaging vendors such as Fiorano. The main drawback of EJB today is probably interoperability (for those that need it). The EJB to CORBA mapping which relies on java2idl is supposed to provide such capability. This is not a mandatory part of the specification, and there is little support for it in the industry. We have selected an intermediate solution where we CORBA-enable EJB servers and allow specifying components in IDL. It's not ideal, but it's a reasonable compromise for the requirements we have. Now, all of this does not mean that you should move to EJB if you already have an application which is using CORBA/Java. This is really a business decision. You should weigh the cost of porting to EJB with the business value. Hope this helps, Doron PS I copied the list, because I think this is an important issue and you'll probably get some more interesting replies. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] > Sent: Friday, September 17, 1999 11:45 PM > To: [EMAIL PROTECTED] > Subject: Regarding EJB Servers > > > > > Hi Doron, > > My name is Sawalia Saurabh. I am software engineer with > Hughes Software > Systems, India, a subsidiary of Hughes Network Systems, USA. > You must be > wondering how I came to know about you. The answer is that I > was going through > the archives of the [EMAIL PROTECTED], and I read the > mails that you had > sent. > > And I hope that by sending this mail to you, I am not causing > any inconvenience > to you. If I am, please do tell me so. I am writing this mail > to you to clear > some doubts that have regarding EJBs. > > Now a days there is a talk about using EJBs for the server > side development. > However if we take a case where most of the server > development has already taken > place and we are using Java and communicating with the > clients through Corba, > what I fail to understand is why should I use EJBs in place > of Corba. What I > mean to say is that I cannot understand what remarkable > (worth consideration) > advantages does the EJB has over Corba. Whatever I have read > about EJBs gave me > the impression that this thing is really like Corba. I have > no problems in > writing the IDL for Corba communication, if that is one of > the advantages of the > Corba enabled EJB servers. My knowledge about EJBs is really > limited, to say the > least. > > Or let us take a case where we are developing the server side > from scratch. For > this also I am at loss to understand why should one go for > EJBs and not for > Corba. Both the technologies are providing the same kind of > facilities , with a > difference that EJBs do the most of the work for you whereas > in Corba you do the > work yourself. But as you know most of the applications that > one develops donot > use all the Corba facilities and services, and hence the > programming is not as > ardrous as is made out to be. In EJBs most of the work will > be done for you by > the EJB server/container pair, but in the most of the > application one develops > one does not utilise all that is provided by the EJB servers. > > My doubts may seem very simplistic, but please do clear them. > > Whatever I could read about EJBS didnot convince me to > abandon Corba and start > using EJBS. Can you provide me with some real advantages that > EJBs have over > Corba? > > Waiting for a reply. > > Warm regards, > > Sawalia Saurabh > [EMAIL PROTECTED] > > =========================================================================== 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".
