Auto-wiring a List using util schema gives NoSuchBeanDefinitionException
java, spring
Solution
This is due to a rather obscure part of @Autowired's behaviour, specified in 3.11.2. @Autowired:
It is also possible to provide all beans of a particular type from the `ApplicationContext` by adding the annotation to a field or method that expects an array of that type...
The same applies for typed collections...
In other words, by saying `@Autowired @Qualifier("myList") List<String>`, you're actually asking for "give me the list of all beans of type `java.lang.String` that have the qualifier "myList".
The solution is mentioned in 3.11.3. Fine-tuning annotation-based autowiring with qualifiers:
If you intend to express annotation-driven injection by name, do not primarily use `@Autowired` - even if is technically capable of referring to a bean name through `@Qualifier` values. Instead, prefer the JSR-250 `@Resource` annotation which is semantically defined to identify a specific target component by its unique name, with the declared type being irrelevant for the matching process.
As a specific consequence of this semantic difference, beans which are themselves defined as a collection or map type cannot be injected via `@Autowired` since type matching is not properly applicable to them. Use `@Resource` for such beans, referring to the specific collection/map bean by unique name.
So use this in your test, and it works fine:
@Resource(name="myList") private List<String> stringList;
Problem
I have a bean that i want to inject with a named list using Spring util namespace `<util:list id="myList">` but Spring is looking for a collection of beans of type String instead. My broken test is: ``` @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration public class ListInjectionTest { @Autowired @Qualifier("myList") private List<String> stringList; @Test public void testNotNull() { TestCase.assertNotNull("stringList not null", stringList); } } ``` My context is: ``` <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util" xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"> <util:list id="myList"> <value>foo</value> <value>bar</value> </util:list> </beans> ``` But I get ``` Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [java.lang.String] found for dependency [collection of java.lang.String]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.beans.factory.annotation.Qualifier(value=myList)} at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:726) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:571) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:412) ``` Which puzzles me rather as I figured this would be the way it was expected to work.