Built-in lifecycle events

Definition

Spring publishes events about its own life: ContextRefreshedEvent when the application is ready and ContextClosedEvent when it shuts down. Listen to them to start work after startup or to clean up on shutdown. Spring Boot adds ApplicationReadyEvent.

Example code

Hooking into startup and shutdown

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.event.ContextClosedEvent;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Component
class Lifecycle {
    @EventListener
    void started(ContextRefreshedEvent event) { System.out.println("application is ready: warm the caches"); }

    @EventListener
    void stopping(ContextClosedEvent event) { System.out.println("application is closing: flush and say goodbye"); }
}

@ComponentScan
class Demo {
    public static void main(String[] args) {
        try (var context = new AnnotationConfigApplicationContext(Demo.class)) {
            System.out.println("doing work");
        }
    }
}

// Output:
// application is ready: warm the caches
// doing work
// application is closing: flush and say goodbye