java listen to ContextRefreshedEvent

Question

I have a classX in my spring application in which I want to be able to find out if all spring beans have been initialized. To do this, I am trying to listen ContextRefreshedEven

Answer 1

A ContextRefreshEvent occurs

when an ApplicationContext gets initialized or refreshed.

so you are on the right track.

What you need to do is declare a bean definition for classX.

Either with @Component and a component scan over the package it's in

@Component
public class X implements ApplicationListener {
    @Override
    public void onApplicationEvent(ContextRefreshedEvent event) {
       //do something if all apps have initialised
    }
}

or with a declaration

Spring will detect that the bean is of type ApplicationListener and register it without any further configuration.

Later Spring version support annotation-based event listeners. The documentation states

As of Spring 4.2, you can register an event listener on any public method of a managed bean by using the @EventListener annotation.

Within the X class above, you could declare an annotated method like

@EventListener
public void onEventWithArg(ContextRefreshedEvent event) {
}

or even

@EventListener(ContextRefreshedEvent.class)
public void onEventWithout() {

}

The context will detect this method and register it as a listener for the specified event type.

The documentation goes into way more detail about the full feature set: conditional processing with SpEL expression, async listeners, etc.

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Just FYI, Java has naming conventions for types, variables, etc. For classes, the convention is to have their names start with an uppercase alphabetic character.