Spring ExitCodeEvent using #EventListener not working - spring

Question

I am trying to catch the event code at the time my springboot app is destroyed. I have the following bean:
#Configuration
public class DestroyListenerConfig {
#Bean
DemoListener demoListenerBean() {
return new DemoListener();
}
private static class DemoListener {
#EventListener
public void exitEvent(ExitCodeEvent event) {
System.out.println("Exit code: " + event.getExitCode());
}
}
}
The bean is registering properly, but when I kill the application, the exitEvent() method is not invoked ( the system out never displays, or when run in debug mode from IDE, it never enters the method).
Am I leaving something out? My impression was this is all that is needed. Thanks.

Answer 1

ExitCodeEvent is published from org.springframework.boot.SpringApplication#exit. So, you need to manually call SpringApplication.exit as below.
#Autowired
ApplicationContext applicationContext;
#GetMapping("/shutdown")
void shutdown() {
SpringApplication.exit(applicationContext, () -> 100);
}
If you want to listen to a bean destroy event then you can use #PreDestroy as following:
Note that if you have multiple beans created for this class, you will get multiple triggers.
//Put this into a #Component(or inside RestController, Controller, Service etc) class
#javax.annotation.PreDestroy
public void destroy() {
System.out.println("Triggered - #PreDestroy.");
}
If your app is a webapp and you want to listen to shutdown event (ideally the contextDestroyed event) you can register a MyServletContextListener to ServletListenerRegistrationBean:
#Bean
ServletListenerRegistrationBean<ServletContextListener> servletListener() {
ServletListenerRegistrationBean<ServletContextListener> srb = new ServletListenerRegistrationBean<>();
srb.setListener(new MyServletContextListener());
return srb;
}
class MyServletContextListener implements ServletContextListener {
#Override
public void contextDestroyed(ServletContextEvent event) {
System.out.println("Callback triggered - ContextListener.");
}
}
Ref:
https://github.com/spring-projects/spring-boot/blob/master/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java#L1332