Weiqi Gao's Observations - ejb tag

Java News Brief (JNB): EJB3 Persistence Jumpstart

Fri, 14 Apr 2006 16:14:17 GMT

As Eric Burke has already mentioned, this month's OCI Java News Brief (JNB) features Jeff Brown's very approachable introduction to JSR-220—EJB3 Persistence Jumpstart:

Jeff Brown: The examples covered here really only begin to cover the capabilities defined by the EJB 3 Persistence specification. The hope is that this information will serve as a practical guide to help developers get started with the API. The best way to get started with the API is to setup a development environment that will allow examples like those discussed in this article to be executed and experimented with. Developers will find that compared with writing JDBC code or even working with other object-to-relational mapping solutions, the EJB 3 Persistence API is very straightforward and easy to work with.

As with all JNB articles, this one gently leads you into the EJB3 code examples by first providing you with the necessary information to set up your development environment. Go ahead, print it out, follow along, and try out the examples.

"Aha, that what they meant when they said EJB3 is easy!" That's my reaction after reading this article. I hope it will be yours too.

EJB 3.0 At The JUG

Fri, 11 Nov 2005 15:37:21 GMT

Yesterday's EJB 3.0 talk at the St. Louis Java Users Group is another one of the more livelier presentations, with a lot of audience interactions.

Raj Patel from Harpoon Technologies began the talk with "I've done a lot of Hibernate work, but I've never done any EJB 2.1s. Those who did probably know how painful it was. EJB 3.0 is going to change that."

Having not read the EJB 3.0 specs myself (I'm waiting for the final version), I liked what I heard. I have seen earlier EJB 3.0 introductions on Java.net and elsewhere, but none of them registered. Again the open Eclipse project with live code helped.

The overwhelming impression I got from yesterday:

EJB 3.0 is very close to Hibernate
EJB 3.0 annotations are orders of magnitudes simpler than EJB 2.1 deployment descriptors
The EJB 2.1 concepts (stateless session beans, stateful session beans, entity beans, message driven beans, activation, passivation, declarative transaction management, declarative security management) all carry over to EJB 3.0. It's the syntax that is simplified
EJB 3.0 does dependency injection with annotations
EJB 3.0 does bean level method invocation interception (AOP) with annotations
EJBQL is similar to HQL (Hibernate query language)

Other observations:

Hibernate will evolve and be a superset of of EJB 3.0 [Update: See Eric Burke's correction]
EJB 3.0 offers some features that shadow the Spring Framework, but not enough to replace it
The embeddable JBoss EJB 3.0 container is cool
Raj says JDO is dead, JDO vendors are going EJB 3.0 (Solarmetric is bought by BEA.)

I guess a more pressing question is this: "Should I adopt EJB 3.0?"

And I think the answer is "It depends." If you've been following the open source developments pretty closely and are using Spring and Hibernate, there is no need to hurry. If you've stuck with the party line and are still doing EJB 2.1 or even 2.0, EJB 3.0 will look very attractive.

Things To Look Into

Thu, 22 Sep 2005 05:06:27 GMT

Continuing my tradition of making a list of things that I ought to know. Here's a few things that I think merits some deeper examination:

JBoss Seam <--JSF&EJB3 framework, no Springs, no Struts, just an app server and me: The announcement is here. The product page is here. The documentation is here. More info here. Accolades here.
LINQ <--Language INtegrated Query, sprinkle selects in C# code: The video is here. The in depth coverage is here. The debate is here, here, and here. And of course the podcast is here (actually here.)

I should list more items, but I really couldn't find anything more that's worth writing about. Indeed, nowadays when Java people meet, the conversation goes something like this: "What's new in the Java world?" "Nothing. Everything is old news now—AOP, Spring, Hibernate, etc."

Don't make me learn Ruby! <scream/>