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https://issues.apache.org/jira/browse/FELIX-5151?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15072534#comment-15072534
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David Jencks commented on FELIX-5151:
-------------------------------------
Hmmm, IIRC up until shortly before we released I had DS still running against
R5, you just didn't get some of the R6 functionality (prototype scope for
instance). I'd be tempted to try to bring that back rather than complicate
what we try to keep track of. Would that work for you?
> Scr Bind methods occasionally gets a null service reference
> -----------------------------------------------------------
>
> Key: FELIX-5151
> URL: https://issues.apache.org/jira/browse/FELIX-5151
> Project: Felix
> Issue Type: Bug
> Components: Declarative Services (SCR)
> Affects Versions: scr-1.8.2
> Environment: Felix 4.4.0, MacOS, Java 8b66
> Reporter: Frank Lyaruu
>
> Hi Felix devs,
> I'm having an intermittent issue with null services being passed to SCR bind
> methods.
> For example in this piece of code:
> @Reference(name = "GitRepository", unbind =
> "removeGitRepository",policy=ReferencePolicy.DYNAMIC,cardinality=ReferenceCardinality.MULTIPLE,target="(bare=true)")
> public synchronized void addGitRepository(GitRepository bareRepository,
> Map<String,Object> settings) {
> if(bareRepository==null) {
> logger.warn("add reference got passed a null. Settings: "+settings);
> }
> // ....
> }
> Most of the time it works fine, but from time to time a null reference gets
> passed.
> The output of the above snippet looks like this:
> [main] WARN com.dexels.consul.repositoryloader.impl.RepositoryListenerImpl -
> add reference got passed a null (thread: main). Settings:
> {url=https://github.com/foo/bar, component.name=dexels.repository.git.bare,
> id=backoffice, token=xxx, service.factoryPid=dexels.repository.git.bare,
> objectClass=[Ljava.lang.String;@60baef24, bare=true, repositoryname=foo,
> service.pid=dexels.repository.git.bare.5fd0cefd-ec30-4418-92d4-a708792590d8,
> component.id=44, event.topics=[Ljava.lang.String;@6692b6c6, service.id=95}
> And then it fails with an NPE when it tries to use the service:
> java.lang.NullPointerException
> at
> com.dexels.consul.repositoryloader.impl.RepositoryListenerImpl.addGitRepository(RepositoryListenerImpl.java:135)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:497)
> at
> org.apache.felix.scr.impl.helper.BaseMethod.invokeMethod(BaseMethod.java:231)
> at
> org.apache.felix.scr.impl.helper.BaseMethod.access$500(BaseMethod.java:39)
> at
> org.apache.felix.scr.impl.helper.BaseMethod$Resolved.invoke(BaseMethod.java:624)
> at org.apache.felix.scr.impl.helper.BaseMethod.invoke(BaseMethod.java:508)
> at org.apache.felix.scr.impl.helper.BindMethod.invoke(BindMethod.java:37)
> at
> org.apache.felix.scr.impl.manager.DependencyManager.doInvokeBindMethod(DependencyManager.java:1608)
> at
> org.apache.felix.scr.impl.manager.DependencyManager.open(DependencyManager.java:1473)
> at
> org.apache.felix.scr.impl.manager.SingleComponentManager.createImplementationObject(SingleComponentManager.java:277)
> at
> org.apache.felix.scr.impl.manager.SingleComponentManager.createComponent(SingleComponentManager.java:127)
> I see this issue pop up from time to time across different services and
> different applications. It is pretty rare, but it does cause instability and
> it is tricky to work around. If I switch to equinox + equinox declarative
> services, this issue goes away.
> It is quite a pain to reproduce, but I have captured it in a debugger a few
> times:
> What I see there is that the
> org.apache.felix.scr.impl.helper.BindMethod.getParameters:605
> return new Object[] {refPair.getServiceObject(), new
> ReadOnlyDictionary( refPair.getRef() )};
> The first array element: refPair.getServiceObject() yields null from time to
> time.
> In RefPair.getServiceObject():
> public T getServiceObject()
> {
> return serviceObjectRef.get();
> }
> Where serviceObjectRef is an AtomicReference, and this is as far as my
> research got.
> I realise this is not the best bug report ever, but is there anyone who has
> seen this before and can shed some light?
> regards, Frank
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