« Posts tagged ejb3

Ejb3 Basics: Deploying Message Driven Beans

February 2, 2010 / posted in Java, Jboss / 2 Comments

Farewell to lazy auto queue generation in JBoss 5

MDB’s were never so easy to deploy and manage when ejb3 first came out. In Jboss 4, all you have to do was annotate a class with @MessageDriven, sprinkle some meta data here and there, stick it in the oven and wham! Instant “I cant believe I made an MDB!?!” In Jboss AS 5 however, MDB queues are no longer automatically created for your application anymore on boot. An inspection of the MDB llifecycle illustrates why:

  1. MDB deploys
  2. No existing Topic/Queue
  3. Topic/Queue is automatically created
  4. MDB is

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Ejb3 basics: Entities

January 29, 2010 / posted in Java / No Comments

Entity Beans? Better than 2.1, I promise.

Ejb3 Entity beans are a type of enterprise java bean construct used to model data used by the ejb framework. The basic idea is to manipulate simple java objects, which represent in concrete terms your database data, and then have the framework handle as much of the plumbing as possible when you persist the data. Persisting means to store for later use in some data repository – usually some kind of database. By persisting these entities within the ejb framework we are able to abstract out tasks like updating a table and its…

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Ejb3 Basics: Bean Managed Transactions

January 14, 2010 / posted in Java, Jboss / 4 Comments

I’m Lazy, why would I want to do my own transaction management?

While its true that the ejb3 container is usually pretty smart about persisting and handling transactions, its also not as smart as a real human being and probably isn’t able to handle complex database transactions and rollbacks. This is where bean managed transactions come in. By handling your own transactions you can avoid some major pitfalls.

The first problem with Container Managed Transactions (CMT) is there’s a time limit imposed by the container (although it’s a configurable timeout). If you are performing a lengthy task and are…

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