Failed to connect to MBean server at port 9001 - health check after ApplicationReadyEvent

Question

I get the error Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:2.3.2.RELEASE:start (pre-integration-test) Could not figure out if the application has started: Failed to connect to MBean server at port 9001: Could not invoke shutdown operation: Connection refused to host: 127.0.0.1; nested exception is: [ERROR] java.net.ConnectException: Connection refused (Connection refused) after I added below health metric and warm up event for the application. Not sure why I get this error. Please advise

How to perform actuator health check after ApplicationReadyEvent? or ApplicationReadyEvent is not required?

@Component
public class Warmup implements HealthIndicator, ApplicationListener<ApplicationReadyEvent> {

    private boolean warmUpOver;

    @Autowired
    public Warmup(){
       
    }

    @Override
    public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
        warmUpMethod();
    }

    public void warmUpMethod(){
        //Once the method is over 
        warmUpOver = true;
    }

    @Override
    public Health health() {
        if(warmUpOver){
            final Health.Builder builder = Health.up();
            return builder.build();
        } else {
            final Health.Builder builder = Health.unknown();
            return builder.build();
        }
    }
}