Sam, I would make the DAO methods non-static to make reuse and testing easier, but that won't have any impact on performance.
The performance problems should primarily come from connecting to the database, executing the query and transfering data across the network. Since you are working with updates, there could also be contention problems.
Look into your connection pool settings and transaction settings to increase performance under load. Also, make sure your update is optimized.
You should let the database or EJB container handle the concurrency by use of transactions. That will be your major issue for performance bottlenecks. It will depend on what you need to change, and how you go about it.
Originally posted by Sam Chako: I think I understand why I should use EJBs to take care of the concurrency problem.
I would actually argue that you *shouldn't* use EJBs just to handle concurrent data base access. There are much more simply options available, such as using a persistence library like Hibernate or even simply using JDBC to handle transactions.
I needed to have much more compelling reasons to go with the complexity of EJBs - in such a case, I would use the transaction handling of the EJB container, of course.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus