Interface SmartInitializingSingleton

public interface SmartInitializingSingleton
Callback interface triggered at the end of the singleton pre-instantiation phase during BeanFactory bootstrap. This interface can be implemented by singleton beans in order to perform some initialization after the regular singleton instantiation algorithm, avoiding side effects with accidental early initialization (for example, from ListableBeanFactory.getBeansOfType(java.lang.Class<T>) calls). In that sense, it is an alternative to InitializingBean which gets triggered right at the end of a bean's local construction phase.

This callback variant is somewhat similar to

invalid reference 
org.springframework.context.event.ContextRefreshedEvent
but doesn't require an implementation of
invalid reference 
org.springframework.context.ApplicationListener
, with no need to filter context references across a context hierarchy etc. It also implies a more minimal dependency on just the beans package and is being honored by standalone ListableBeanFactory implementations, not just in an
invalid reference 
org.springframework.context.ApplicationContext
environment.

NOTE: If you intend to start/manage asynchronous tasks, preferably implement

invalid reference 
org.springframework.context.Lifecycle
instead which offers a richer model for runtime management and allows for phased startup/shutdown.
Since:
4.1
Author:
Juergen Hoeller
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    afterSingletonsInstantiated()
    Invoked right at the end of the singleton pre-instantiation phase, with a guarantee that all regular singleton beans have been created already.

  • Method Details

    • afterSingletonsInstantiated

      void afterSingletonsInstantiated()
      Invoked right at the end of the singleton pre-instantiation phase, with a guarantee that all regular singleton beans have been created already. ListableBeanFactory.getBeansOfType(java.lang.Class<T>) calls within this method won't trigger accidental side effects during bootstrap.

      NOTE: This callback won't be triggered for singleton beans lazily initialized on demand after BeanFactory bootstrap, and not for any other bean scope either. Carefully use it for beans with the intended bootstrap semantics only.