Spring question: Is field name used to match on bean name when @Autowired matches several beans by type?
Execute the main method in Application (run ./mvnw spring-boot:run).
Note what is written to standard out by PublisherUser.printDebugInfo() which is a @PostConstruct method. The output is:
publishers.length: 2
publisherImplOne.getClass(): PublisherImplOne
publisherImplTwo.getClass(): PublisherImplTwo
Spring configuration and main method is located in Application.
Publisher is an interface, which is implemented by two different beans: PublisherImplOne and PublisherImplTwo.
PublisherUser is registered as a Spring bean, and has multiple fields into which beans of type Publisher are
@Autowired like this:
@Autowired
private Publisher publisherImplOne; // <== PublisherImplOne instance is injected - matches Application.publisherImplOne() by name
@Autowired
private Publisher publisherImplTwo; // <== PublisherImplTwo instance is injected - matches Application.publisherImplTwo() by name
@Autowired
private Publisher[] publishers; // <== Will get PublisherImplOne and PublisherImplTwo are both injected
Note that the two fields of type Publisher both have the same names as a bean (e.g. the publisherImplOne field has the
same name as the bean defined by the @Bean method Application.publisherImplOne()).
As long as the field names and bean names match the program works. If we rename one of the fields, then Spring will
complain that two beans both match the type of the @Autowired field.
Is this expected behavior? We can't find it documented anywhere.