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@Resource For A Non-EJB

Mark Garland
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Joined: Nov 11, 2006
Posts: 226
Hi all,

I have written a standard Java class (not an EJB) which I have packaged as a JAR within an EAR. This Java Class will put things on a queue when requested.

Rather than perform a manual JNDI lookup for the Queue and Connection Factory, I used the @Resource annotation, and assumed that because it was within a Container (GlassFish) that this would work.
I am pretty confident that the annotation/queue/connectionfactory is set up correctly because the deployment through NetBeans fails otherwise.
However, I keep getting a NullPointerException when the code is executed, so the @Resource annotation isn't working.

Does the @Resource annotation only work in EJBs? Or is this a GlassFish quirk?

Thanks,

MG


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Jaikiran Pai
Marshal

Joined: Jul 20, 2005
Posts: 10069
    
163

Mark Garland wrote:
Does the @Resource annotation only work in EJBs? Or is this a GlassFish quirk?



@Resource and other similar EE injection constructs work only with managed classes like servlets, EJBs, managed beans etc. They won't work with plain Java classes.


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Mark Garland
Ranch Hand

Joined: Nov 11, 2006
Posts: 226
Hi Jaikiran,

Thanks for your quick and accurate reply.

I've removed the @Resource annotations and put in a manual JNDI lookup, and all is working great - thanks!

The @Resource annotation not working in a POJO which is sat in a container feels a bit of a shame if honest. A lot of the annotations are great for reducing repeating boilerplate code, yet I'd be forced to convert my POJOs to EJBs if I wanted to use them even though the container is capable. Just feels like a missed opportunity to me.

Thanks once again for your help - much appreciated.

MG
Jaikiran Pai
Marshal

Joined: Jul 20, 2005
Posts: 10069
    
163

Mark Garland wrote: A lot of the annotations are great for reducing repeating boilerplate code, yet I'd be forced to convert my POJOs to EJBs if I wanted to use them even though the container is capable. Just feels like a missed opportunity to me.



Java EE6 introduces Managed Beans which plugs this gap. A Managed Bean is a POJO which can have injection, lifecycle callbacks and interceptors. It however doesn't have any transactional, security related semantics unlike EJBs - which is understandable.
Jayavardhan geepi
Ranch Hand

Joined: Jul 21, 2010
Posts: 66
Hi,

I tried to use resource injection in a servlet with name parameter set to jndi name (which works in manual look up) in JBoss 4.2.x.x.

It is not working. Properties are null at run time.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: @Resource For A Non-EJB