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https://issues.apache.org/jira/browse/ARIES-1957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17253784#comment-17253784
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Harrison Tarr commented on ARIES-1957:
--------------------------------------
Hi just chiming in, I'm also running into this error. I'm trying to use generic
parameters on my class but get a class cast exception when it tries to go from
my `GenericWrapper<SpecificClass>` to `GenericWrapper<Object`, so I thought of
passing the generic as an argument to the constructor - maybe it would inform
the class that its type should be `SpecificClass` and not `Object`
> Using Generic types throws Unknown type exception
> -------------------------------------------------
>
> Key: ARIES-1957
> URL: https://issues.apache.org/jira/browse/ARIES-1957
> Project: Aries
> Issue Type: Bug
> Components: Blueprint
> Affects Versions: blueprint-core-1.8.0
> Environment: Karaf 4.2.6
> JDK 11.5
> Reporter: Jerome MICHEL
> Assignee: Jean-Baptiste Onofré
> Priority: Major
> Fix For: blueprint-core-1.8.4, blueprint-core-1.9.1
>
>
> We are currently trying to migrate from Karaf 4.1.1 which uses Apache Aries
> Blueprint v1.8.0 to Karaf 4.2.6 which uses Aries Blueprint v1.10.2
> While we were able to handle beans with Generic constructors in the previous
> version, any usage of Generics now throws a RuntimeException saying the type
> is not known.
> With this definition in Blueprint :
> {code:java}
> <bean id="sharedModel" class="javafx.beans.property.SimpleObjectProperty>
> <argument>
> <bean class="com.example.MySuperModel" />
> </argument>
> </bean>{code}
> The definition of the javaFX class is like :
>
>
> {code:java}
> public class SimpleObjectProperty<T> extends ObjectPropertyBase<T> {
> [...]
> public SimpleObjectProperty() {
> ...
> }
> public SimpleObjectProperty(T var) {
> ...
> }
> }{code}
> The instanciation of this bean result in :
>
>
> {code:java}
> 2019-12-05T09:35:44,162 | ERROR | Blueprint Extender: 3 |
> org.apache.aries.blueprint.container.BlueprintContainerImpl | 102 -
> org.apache.aries.blueprint.core - 1.10.2 | Unable to start container for
> blueprint bundle com.test.hmi/1.4.0.SNAPSHOT
> org.osgi.service.blueprint.container.ComponentDefinitionException: Unable to
> instantiate components
> at
> org.apache.aries.blueprint.container.BlueprintContainerImpl.instantiateEagerComponents(BlueprintContainerImpl.java:741)
> ~[102:org.apache.aries.blueprint.core:1.10.2]
> at
> org.apache.aries.blueprint.container.BlueprintContainerImpl.doRun(BlueprintContainerImpl.java:433)
> [102:org.apache.aries.blueprint.core:1.10.2]
> at
> org.apache.aries.blueprint.container.BlueprintContainerImpl.run(BlueprintContainerImpl.java:298)
> [102:org.apache.aries.blueprint.core:1.10.2]
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
> at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
> at
> org.apache.aries.blueprint.container.ExecutorServiceWrapper.run(ExecutorServiceWrapper.java:106)
> [102:org.apache.aries.blueprint.core:1.10.2]
> at
> org.apache.aries.blueprint.utils.threading.impl.DiscardableRunnable.run(DiscardableRunnable.java:45)
> [102:org.apache.aries.blueprint.core:1.10.2]
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
> at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
> [?:?]
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
> [?:?]
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
> [?:?]
> at java.lang.Thread.run(Thread.java:834) [?:?]
> Caused by: java.lang.RuntimeException: Unknown type T
> at
> org.apache.aries.blueprint.utils.generics.TypeInference.getParameters(TypeInference.java:449)
> ~[?:?]
> at
> org.apache.aries.blueprint.utils.generics.TypeInference.match(TypeInference.java:262)
> ~[?:?]
> at
> org.apache.aries.blueprint.utils.generics.TypeInference.findMatching(TypeInference.java:231)
> ~[?:?]
> at
> org.apache.aries.blueprint.utils.generics.TypeInference.findMatchingConstructors(TypeInference.java:125)
> ~[?:?]
> at
> org.apache.aries.blueprint.container.BeanRecipe.findMatchingConstructors(BeanRecipe.java:373)
> ~[?:?]
> at
> org.apache.aries.blueprint.container.BeanRecipe.getInstanceFromType(BeanRecipe.java:346)
> ~[?:?]
> at
> org.apache.aries.blueprint.container.BeanRecipe.getInstance(BeanRecipe.java:283)
> ~[?:?]
> at
> org.apache.aries.blueprint.container.BeanRecipe.internalCreate2(BeanRecipe.java:685)
> ~[?:?]
> at
> org.apache.aries.blueprint.container.BeanRecipe.internalCreate(BeanRecipe.java:666)
> ~[?:?]
> at
> org.apache.aries.blueprint.di.AbstractRecipe$1.call(AbstractRecipe.java:81)
> ~[?:?]
> at java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[?:?]
> at
> org.apache.aries.blueprint.di.AbstractRecipe.create(AbstractRecipe.java:90)
> ~[?:?]
> at
> org.apache.aries.blueprint.container.BlueprintRepository.createInstances(BlueprintRepository.java:360)
> ~[?:?]
> at
> org.apache.aries.blueprint.container.BlueprintRepository.createAll(BlueprintRepository.java:190)
> ~[?:?]
> at
> org.apache.aries.blueprint.container.BlueprintContainerImpl.instantiateEagerComponents(BlueprintContainerImpl.java:737)
> ~[?:?]
> ... 12 more
> {code}
>
> We tried to investigate around this error trying to know if we made a mistake
> on our side.
> As far as we tested and tried to debug in the blueprint's classes, we found
> that when blueprint is matching constructors from what the class has and the
> parameters he received only _Class_ and _ParametrizedType_ are handled in
> _TypeInference#getParameters(Type)_. But due to genericity, we arrived with a
> _TypeVariable,_ which is of type T with Object as generic bound.
> So maybe this type can also be handled like other cases ?
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