Avoid creation of lazy candidates when the primary bean is injected [SPR-14611]

[spring-projects-issues]

Asaf Romano opened SPR-14611 and commented

Consider the following code in a Config class:

    @Bean(name = "sharedExecutorService")
    @Primary
    @Lazy
    public ExecutorService sharedExecutorService()
    {
        System.out.println("In sharedExecutorService");
        ExecutorService executorService = Executors.newFixedThreadPool(5);
        System.out.println(String.format("Created: %s", executorService));
        return executorService;
    }

    @Bean(name = "localExecutorService1")
    @Lazy
    public ExecutorService localExecutorService1()
    {
        System.out.println("In localExecutorService1");
        ExecutorService executorService = sharedExecutorService();
        System.out.println(String.format("Created: %s", executorService));
        return executorService;
    }

    @Bean(name = "localExecutorService2")
    @Lazy
    public ExecutorService localExecutorService2()
    {
        System.out.println("In localExecutorService2");
        ExecutorService executorService = sharedExecutorService();
        System.out.println(String.format("Created: %s", executorService));
        return executorService;
    }

Later on, someone injects the primary bean as follows:

@Inject
private ExecutorService executorService;

The expectation is for the primary bean to be constructed and injected at this point, but for the other two beans not to be constructed yet (as they are lazy). What seems to happen, however, is that all three beans are constructed at this point (albeit the primary bean is successfully injected).

Please note that this issue seems to be quite similar to #18314

---

Affects: 4.3.2

Issue Links:

• findDefaultEntityManagerFactory should consider EMF bean's primary flag [SPR-7549] #12206 findDefaultEntityManagerFactory should consider EMF bean's primary flag
• BeanFactoryAnnotationUtils.qualifiedBeanOfType should not instantiate all beans of given type before checking qualifier [SPR-13741] #18314 BeanFactoryAnnotationUtils.qualifiedBeanOfType should not instantiate all beans of given type before checking qualifier

Referenced from: commits c4fcdb6, a7849b2

[spring-projects-issues]

Juergen Hoeller commented

I've addressed this through a revision of DefaultListableBeanFactory's resolution algorithms, only resolving bean instances when already available and otherwise operating against the bean type until an instance has actually been selected for exposure. This still allows for proper introspection of primary candidates and priority values but does not trigger unnecessary bean creation.