Polish "Add support for Async invocation in a native image"

This registers the hints if the annotation post processor is active,
rather than statically.

See gh-28710

Author: snicoll

spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncAnnotationBeanPostProcessor.java

@@ -25,9 +25,14 @@
 
 import org.springframework.aop.framework.autoproxy.AbstractBeanFactoryAwareAdvisingPostProcessor;
 import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.RuntimeHintsRegistrar;
+import org.springframework.aot.hint.support.RuntimeHintsUtils;
 import org.springframework.beans.factory.BeanFactory;
+import org.springframework.context.annotation.ImportRuntimeHints;
 import org.springframework.core.task.TaskExecutor;
 import org.springframework.lang.Nullable;
+import org.springframework.scheduling.annotation.AsyncAnnotationBeanPostProcessor.AsyncAnnotationRuntimeHints;
 import org.springframework.util.Assert;
 import org.springframework.util.function.SingletonSupplier;
 
@@ -62,6 +67,7 @@
  * @see ScheduledAnnotationBeanPostProcessor
  */
 @SuppressWarnings("serial")
+@ImportRuntimeHints(AsyncAnnotationRuntimeHints.class)
 public class AsyncAnnotationBeanPostProcessor extends AbstractBeanFactoryAwareAdvisingPostProcessor {
 
 	/**
@@ -154,4 +160,13 @@ public void setBeanFactory(BeanFactory beanFactory) {
 		this.advisor = advisor;
 	}
 
+	static class AsyncAnnotationRuntimeHints implements RuntimeHintsRegistrar {
+
+		@Override
+		public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
+			RuntimeHintsUtils.registerAnnotation(hints, Async.class);
+		}
+
+	}
+
 }

spring-context/src/main/java/org/springframework/scheduling/annotation/SchedulingRuntimeHints.java

@@ -1,5 +1,2 @@
-org.springframework.aot.hint.RuntimeHintsRegistrar= \
-org.springframework.scheduling.annotation.SchedulingRuntimeHints
-
 org.springframework.beans.factory.aot.BeanRegistrationAotProcessor= \
 org.springframework.context.aot.ReflectiveProcessorBeanRegistrationAotProcessor