[jboss-jira] [JBoss JIRA] (WFLY-4251) @DependsOn not adherent to Java EE 7 spec

[Matteo Mortari (JIRA)]

    [ https://issues.jboss.org/browse/WFLY-4251?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13032577#comment-13032577 ] 

Matteo Mortari commented on WFLY-4251:
--------------------------------------

added Conclusion paragraph.

> @DependsOn not adherent to Java EE 7 spec
> -----------------------------------------
>
>                 Key: WFLY-4251
>                 URL: https://issues.jboss.org/browse/WFLY-4251
>             Project: WildFly
>          Issue Type: Bug
>          Components: EE, EJB
>    Affects Versions: 8.2.0.Final
>            Reporter: Matteo Mortari
>            Assignee: Jason Greene
>            Priority: Minor
>         Attachments: 20150114.wildfly82_dependson.zip
>
>
> *Premise*: actually, I'm leveraging this misalignment for implementing a functionality; however, I don't believe is correct behavior accordingly to Java EE 7 specs, hence reporting it.
> h5. Executive summary
> With reference to attached reproducer, and example scenario below; the {{@DependsOn}} annotation on wildfly 8.2.0.Final works also against Stateless EJB, but accordingly to Java EE 7 specs {{@DependsOn}} annotation:
> {quote}
> Used to express an initialization dependency between singleton components.
> {quote}
> h5. Detailed description
> Assume you have a {{@Singleton}} and while on {{@PreDestroy}} you need to persist some entities, which are normally done through a Stateless EJB serving as a "Controller"/"DAO", example:
> {code:java}
> @Singleton
> @Startup
> //@DependsOn(value={"AStatelessEJB"})
> public class SingletonEJB {
> 	private static final Logger LOG = LoggerFactory.getLogger(SingletonEJB.class);
> 	
> 	@EJB
> 	private AStatelessEJB sl;
> 	
> 	@PostConstruct
> 	public void init() {
> 		LOG.info("SingletonEJB is here.");
> 	}
> 	
> 	@PreDestroy
> 	public void shutdown() {
> 		LOG.info("SingletonEJB is about to shutdown...");
> 		sl.dummyPersist(); // line #30
> 	}
> }
> {code}
> with the {{@DependsOn}} annotation currently commented, and where:
> {code:java}
> @Stateless(name="AStatelessEJB", mappedName="AStatelessEJB")
> public class AStatelessEJB {
> 	private static final Logger LOG = LoggerFactory.getLogger(AStatelessEJB.class);
> 			
> 	public void dummyPersist() {
> 		LOG.info("called dummyPersist().");
> 	}
> }
> {code}
> just for simulating a "controller"/"DAO" example as a Stateless EJB.
> Invoking wildfly shutdown will produce the following stacktrace:
> {noformat}
> 19:26:34,570 INFO  [org.jboss.as] (Controller Boot Thread) JBAS015874: WildFly 8.2.0.Final "Tweek" started in 98671ms - Started 347 of 399 services (107 services are lazy, passive or on-demand)
> 19:26:45,136 INFO  [org.wildfly.extension.undertow] (MSC service thread 1-7) JBAS017535: Unregistered web context: /wildfly82-dependson
> ...
> 19:26:45,213 INFO  [com.acme.wildfly82_dependson.SingletonEJB] (ServerService Thread Pool -- 24) SingletonEJB is about to shutdown...
> ...
> 19:26:45,213 ERROR [org.jboss.as.ejb3.invocation] (ServerService Thread Pool -- 24) JBAS014134: EJB Invocation failed on component AStatelessEJB for method public void com.acme.wildfly82_dependson.AStatelessEJB.dummyPersist(): org.jboss.as.ejb3.component.EJBComponentUnavailableException: 
> JBAS014559: Invocation cannot proceed as component is shutting down
> ...
> 	at com.acme.wildfly82_dependson.AStatelessEJB$$$view2.dummyPersist(Unknown Source) [classes:]
> 	at com.acme.wildfly82_dependson.SingletonEJB.shutdown(SingletonEJB.java:30) [classes:]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.8.0_05]
> {noformat}
> However, with the annotation un-commented and active:
> {noformat}
> 19:21:44,713 INFO  [org.jboss.as] (Controller Boot Thread) JBAS015874: WildFly 8.2.0.Final "Tweek" started in 109462ms - Started 347 of 399 services (107 services are lazy, passive or on-demand)
> ...
> 19:22:17,908 INFO  [org.wildfly.extension.undertow] (MSC service thread 1-3) JBAS017535: Unregistered web context: /wildfly82-dependson
> 19:22:17,971 INFO  [org.wildfly.extension.undertow] (MSC service thread 1-8) JBAS017532: Host default-host stopping
> ...
> 19:22:18,017 INFO  [com.acme.wildfly82_dependson.SingletonEJB] (ServerService Thread Pool -- 68) SingletonEJB is about to shutdown...
> 19:22:18,033 INFO  [com.acme.wildfly82_dependson.AStatelessEJB] (ServerService Thread Pool -- 68) called dummyPersist().
> ...
> 19:22:18,236 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-4) JBAS015877: Stopped deployment wildfly82-dependson.war (runtime-name: wildfly82-dependson.war) in 334ms
> {noformat}
> But I'm puzzled because as stated above the Java EE specs javadoc describe the {{@DependsOn}} annotation as _Used to express an initialization dependency between singleton components._ , therefore although I'm happy it actually works, I'm puzzled about the misalignments, hence reporting it.
> h5. Conclusions
> I have the following questions, please?
> * Can you clarify if this is the correct or intended behavior of the annotation on Wildfly?
> * In the case the implementation of this annotation will be put in future release to adhere strictly to the Java EE 7 specs, what should be the correct way to implement the above scenario, in an alternative way?
> (If this instead will not be modified, in other words the Wildfly implementation of the annotation will be more wide than the JavaEE 7 specs, then I got nothing to do as the application is already working and sorry for this report, but I thought worthy to mention).



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