Spring - differences between @Named and @Component

Question

I am trying to understand the differences between these two annotations and how they affect injection in Spring. Consider the following piece of code -

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Component
public @interface ExternalPropertiesHolder {}

When I mark a class with this annotation -

@ExternalPropertiesHolder
public class SomeProperties {}

and then this dependency is injected using @Inject, it works perfectly -

@Service
public class SomeService {
    private SomeProperties someProperties;

    @Inject
    public SomeService(SomeProperties someProperties) {
        this.someProperties = someProperties;
    }
}

However, when I replace @Component with @Named -

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Named           // --> Here!
public @interface ExternalPropertiesHolder {}

Then the injection fails with the usual bean not found exception -

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.hogehoge.SomeProperties] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}

I searched the Spring reference documentation, and all it has to say about the difference is this -

JSR-330 does not provide a composable model, just a way to identify named components.

What does that mean? Does it mean that I cannot use @Named to compose a custom marker like this? Or is there something else?

P.S.: Of course by @Component I am referring to org.springframework.stereotype.Component and by @Named I am referring to javax.inject.Named.

Answer 1

So I got the answer directly from Juergen Hoeller. According to him, this line -

JSR-330 does not provide a composable model, just a way to identify named components.

means that the javax.inject.Named can only be declared directly on a given bean class. The composable annotation story just works with Spring's own annotations, which is exactly what I suspected.