[weld-dev] Application scoped bean and its lifecycle

[Martin Kouba]

Ok, now I know what's going on.

The event with payload "Application context initialized." comes directly 
from Weld. Whereas the second one java.lang.Object at 48813e62 comes from 
PAX CDI [1].

Up to version 2.2 Weld did not fire @Initialized/@Destroyed events for 
@ApplicationScoped for non-web modules. The behavior changed in 2.3 - 
see also WELD-1821 [2].

This explains the events fired twice.

WRT Test bean instance created twice - the problem is that 
@Destroyed(ApplicationScoped.class) event is fired after the actual 
destruction. So if you declare an observer on an @ApplicationScoped 
you're entering the "undefined behavior zone". In Weld, the Test bean is 
created again.

I've created WELD-2389 [3] to track this issue.

Thanks,

Martin

[1]
https://github.com/ops4j/org.ops4j.pax.cdi/blob/master/pax-cdi-weld/src/main/java/org/ops4j/pax/cdi/weld/impl/WeldCdiContainer.java#L154

[2]
https://issues.jboss.org/browse/WELD-1821

[3]
https://issues.jboss.org/browse/WELD-2389


Dne 22.5.2017 v 09:57 Alex Sviridov napsal(a):
> Hi Martin
> 
> Thank you for your answer.
> 
> 1) I don't inject Test class anywhere.
> 2) I modified init and destroy methods:
>      public void init(@Observes @Initialized(ApplicationScoped.class) 
> Object init) {
>          System.out.println(init);
>          System.out.println("Test was initialized");
>      }
> 
>      public void destroy(@Observes @Destroyed(ApplicationScoped.class) 
> Object init) {
>          System.out.println(init);
>          System.out.println("Test was destroyed.");
>      }
> 
> Now on bundle start:
> 
> Test was created.
> Application context initialized.
> Test was initialized
> java.lang.Object at 48813e62
> Test was initialized
> 
> Now on bundle stop:
> 
> java.lang.Object at 48813e62
> Test was destroyed.
> Test was created.
> Application context destroyed.
> Test was destroyed.
> 
> 
>     Понедельник, 22 мая 2017, 10:48 +03:00 от Martin Kouba
>     <mkouba at redhat.com>:
> 
>     Hi Alex,
> 
>     this looks really weird. Could you try to print out the event payload,
>     e.g. System.out.println(init)?
> 
>     Also you should be always very careful when using code inside the
>     no-args constructor of a normal-scoped bean -> it will be also executed
>     when creating a client proxy. In your case, if you do @Inject Test and
>     invoke any method then you will also see "Test was created" printed
>     twice.
> 
>     Martin
> 
>     Dne 22.5.2017 v 08:50 Alex Sviridov napsal(a):
>      > Hi all
>      >
>      > I use pax-cdi -1.0.0.RC2 and weld 2.3.5.Final and this is my test
>     class:
>      >
>      > import javax.enterprise.context.ApplicationScoped;
>      > import javax.enterprise.context.Destroyed;
>      > import javax.enterprise.context.Initialized;
>      > import javax.enterprise.event.Observes;
>      >
>      > @ApplicationScoped
>      > public class Test {
>      >
>      > public Test() {
>      > System.out.println("Test was created.");
>      > }
>      >
>      > public void init(@Observes @Initialized(ApplicationScoped.class)
>     Object
>      > init) {
>      > System.out.println("Test was initialized");
>      > }
>      >
>      > public void destroy(@Observes @Destroyed(ApplicationScoped.class)
>      > Object init) {
>      > System.out.println("Test was destroyed.");
>      > }
>      > }
>      >
>      > When I start test-bundle I see the following output:
>      > Test was created.
>      > Test was initialized
>      > Test was initialized
>      > When I stop test-bundle I see the following output:
>      > Test was destroyed.
>      > Test was created.
>      > Test was destroyed.
>      >
>      > So as result this bean was two times created, two times
>     initialized and two
>      > times destroyed.
>      >
>      > I expected that this bean must be once created, one initialized
>     and once
>      > destroyed.
>      >
>      > Is this a bug that must be reported or my mistake?
>      >
>      > --
>      > Alex Sviridov
>      >
>      >
>      > _______________________________________________
>      > weld-dev mailing list
>      > weld-dev at lists.jboss.org <mailto:weld-dev at lists.jboss.org>
>      > https://lists.jboss.org/mailman/listinfo/weld-dev
>      >
> 
>     -- 
>     Martin Kouba
>     Senior Software Engineer
>     Red Hat, Czech Republic
> 
> 
> 
> -- 
> Alex Sviridov

-- 
Martin Kouba
Senior Software Engineer
Red Hat, Czech Republic