Question on Applicability of J2EE Technology

[Santosh Pasupuleti]

The data comes to the application of interest through a specialized custom feed that directly updates a relational database. If the application is expected to receive between fifty to hundred concurrent hits in their site, which of the following java based technologies may be best suited ?

a. Servlets and JSP for presentation and session beans with DAO for retreival
b. Servlets and JSP for presentation and CMP beans for retreival
c. Servlets and JSP for presentation and BMP beans for retreival
d. Applets for presentation and either Session or Entity beans for retreival
e. Servlets and JSP for presentation with Java classes encapsulating all database access.

Options a and e look the candidates for the question.

Please give your options and the reason behind your option. I am always confused about when I should consider EJBs. Please give me your tip.

Please suggest me the book or material which helps me on this topic.

Regards
Santosh

[Ajith Kallambella]

If both concurrent access and transaction support are required, then EJBs are candidates. If only concurrent access is required and no transaction support ie., if data access is read-only, then one can do without EJBs and just use JSP/Servlet/DAO combination. So IMO the key is transaction support.

[Tom Adams]

I would take it that the question is about performance with the high? hit numbers. And since it says "updates a db" the implication is transactions will be required. I also think some would argue better performance with EJB/Entity Beans due to caching options.

b,c and d include some EJB flavor...

I would pass on b because CMP is usally not seen as high performing because of the non-optimized SQL.

C appears to be the best choice, Entity Bean for EJB transaction, maybe caching and BMP for performance.

I would pass on d - most SCEA questions do not view Session EJBs as viable for DB operations...also the applet would require direct server connects and would not scale well.

[Peer Reynders]

Originally posted by Tom Adams:
And since it says "updates a db" the implication is transactions will be required.

Actually the quote should be:

The data comes ... through a specialized custom feed that directly updates a relational database.

There is no hint that the "fifty to hundred concurrent hits" (and the associated J2EE application) cause any update at all. It does imply that the J2EE application can never assume that it currently holds the most recent data as it does not "own" the DB.

Originally posted by Ajith Kallambella:
If only concurrent access is required and no transaction support ie., if data access is read-only, then one can do without EJBs and just use JSP/Servlet/DAO combination.

With this interpretation (e) looks like a good candidate.
[ November 01, 2005: Message edited by: Peer Reynders ]