Doc: Constructor injection of arrays and collections [SPR-14332]

[spring-projects-issues]

Fabrizio Cucci opened SPR-14332 and commented

Hi spring staff,

I'm writing to signal a documentation improvement related to this Stack Overflow question.

I'm referring to this section and specifically the following statement:

??As a specific consequence of this semantic difference, beans that are themselves defined as a collection or map type cannot be injected through @Autowired, because type matching is not properly applicable to them. Use @Resource for such beans, referring to the specific collection or map bean by unique name.??

There are a couple of implicit, but important, consequences of the previous statement:

1. since @Autowired cannot be used to inject beans that are themselves defined as a collection or map and @Resource is not applicable to constructors, constructor injection of those beans is currently not possible;
2. what mentioned before applies also to arrays, besides collections and maps.

Whether this is a limitation or a design choice is debatable but still, for the time being, I think the documentation should be more explicit about those points.

Thanks,
Fabrizio

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Affects: 4.3 RC2

Reference URL: http://stackoverflow.com/questions/37622337/constructor-injection-and-arrays-with-spring

Issue Links:

• Allow for normal bean wiring semantics for types assignable to Map [SPR-7915] #12570 Allow for normal bean wiring semantics for types assignable to Map
• @Autowired does not work for target bean of type Collection [SPR-12180] #16794 @Autowired does not work for target bean of type Collection

[spring-projects-issues]

Juergen Hoeller commented

Hopefully to the better, @Autowired can actually match collection/map and array types as of 4.3! So that documentation section actually needs to be updated towards 4.3's capabilities...