Switch BackgroundPreinitializer to implementing Ordered

Closes gh-30905

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java

@@ -30,7 +30,7 @@ import org.springframework.boot.context.event.SpringApplicationEvent;
 import org.springframework.boot.context.logging.LoggingApplicationListener;
 import org.springframework.context.ApplicationListener;
 import org.springframework.core.NativeDetector;
-import org.springframework.core.annotation.Order;
+import org.springframework.core.Ordered;
 import org.springframework.format.support.DefaultFormattingConversionService;
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
 import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;
@@ -49,8 +49,7 @@ import org.springframework.http.converter.support.AllEncompassingFormHttpMessage
  * @author Sebastien Deleuze
  * @since 1.3.0
  */
-@Order(LoggingApplicationListener.DEFAULT_ORDER + 1)
-public class BackgroundPreinitializer implements ApplicationListener<SpringApplicationEvent> {
+public class BackgroundPreinitializer implements ApplicationListener<SpringApplicationEvent>, Ordered {
 
 	/**
 	 * System property that instructs Spring Boot how to run pre initialization. When the
@@ -72,6 +71,11 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 				&& Runtime.getRuntime().availableProcessors() > 1;
 	}
 
+	@Override
+	public int getOrder() {
+		return LoggingApplicationListener.DEFAULT_ORDER + 1;
+	}
+
 	@Override
 	public void onApplicationEvent(SpringApplicationEvent event) {
 		if (!ENABLED) {