Unique XML-specified constructor not accepted in case of unresolvable name [SPR-13987]

[spring-projects-issues]

Thibault Kruse opened SPR-13987 and commented

To reproduce:

<bean id="myExecutor" class="java.util.concurrent.ScheduledThreadPoolExecutor">
     <constructor-arg name="corePoolSize" index="0" type="int" value="1" />
     <!-- works: <constructor-arg index="0" type="int" value="1" /> -->
</bean>

fails with:

Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myExecutor' defined in class path resource [applicationContext-test.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [int]: Ambiguous constructor argument types - did you specify the correct bean references as constructor arguments?

Class ScheduledThreadPoolExecutor has only one 1-arg constructor:
public ScheduledThreadPoolExecutor(int corePoolSize)

If not a bug, I would suggest improving the error message and the documentation in spring-beans.xsd.

Also see one of the comments here from 2013:
http://stackoverflow.com/questions/17387544/unsatisfied-dependency-expressed-through-constructor-argument-with-index-0-of-ty

---

Affects: 4.2.4

Issue Links:

• BeanCreationException for factory-method-created bean [SPR-14303] #18875 BeanCreationException for factory-method-created bean ("is duplicated by")
• Improve core container exception meta-data [SPR-13968] #18540 Improve core container exception meta-data
• Consistent resolution of factory method exceptions [SPR-13985] #18557 Consistent resolution of factory method exceptions

[spring-projects-issues]

Juergen Hoeller commented

Looks like this is because the java.util.concurrent.ScheduledThreadPoolExecutor (like all of the JDK's rt.jar) is not compiled with -parameters, so we can't resolve the parameter name... However, unfortunately, we insist on resolving the name even in cases where the constructor specification is unique in any case! And indeed, the wording of the exception message should be improved, but for this particular case, the configuration should actually just get accepted and work fine at runtime.

Juergen

[spring-projects-issues]

Juergen Hoeller commented

I've revised our ConstructorArgumentValues holder to leniently allow for matches if the required name is not resolvable.

Juergen

[spring-projects-issues]

Guram Savinov commented

1. Why name is a problem for resolving if index specified?
2. Why constructor resolver doesn't understand that if I specify only one argument I want constructor with one argument? For example this doesn't work:

<bean id="blockingQueue" class="java.util.concurrent.ArrayBlockingQueue" c:capacity="100" />
This class has three constructors with one, two and three arguments.

[spring-projects-issues]

Juergen Hoeller commented

As per these changes in 4.3 RC1, your scenarios should work fine. Have you tried RC1, or even better RC2 or the latest 4.3.0.BUILD-SNAPSHOT?