Addressing PR review

Signed-off-by: chickenchickenlove <[email protected]>

Author: chickenchickenlove

spring-kafka/src/main/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessor.java

@@ -407,19 +407,18 @@ public Object postProcessAfterInitialization(final Object bean, final String bea
 					this.logger.debug(() -> annotatedMethods.size() + " @KafkaListener methods processed on bean '"
 							+ beanName + "': " + annotatedMethods);
 				}
-				Set<Method> methodsWithHandler = MethodIntrospector.selectMethods(targetClass,
-						(ReflectionUtils.MethodFilter) method ->
-								AnnotationUtils.findAnnotation(method, KafkaHandler.class) != null);
-				boolean hasMethodLevelKafkaHandlerAnnotation = !methodsWithHandler.isEmpty();
 				if (hasClassLevelListeners) {
+					Set<Method> methodsWithHandler = MethodIntrospector.selectMethods(targetClass,
+							(ReflectionUtils.MethodFilter) method ->
+									AnnotationUtils.findAnnotation(method, KafkaHandler.class) != null);
+
+					if (methodsWithHandler.isEmpty()) {
+						throw new IllegalStateException("No Kafka listener methods in bean: " + bean);
+					}
+
 					List<Method> multiMethods = new ArrayList<>(methodsWithHandler);
 					processMultiMethodListeners(classLevelListeners, multiMethods, targetClass, bean, beanName);
 				}
-
-				if (!hasMethodLevelListeners && hasClassLevelListeners &&
-					!hasMethodLevelKafkaHandlerAnnotation) {
-					throw new IllegalStateException("No Kafka listener methods in bean: " + bean);
-				}
 			}
 		}
 		return bean;

spring-kafka/src/test/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessorTests.java

@@ -41,7 +41,8 @@ void ctx_should_be_fail_to_register_bean_when_no_listener_methods_exist() {
 
 		assertThatExceptionOfType(BeanCreationException.class)
 				.isThrownBy(ctx::refresh)
-				.withMessageContaining("No kafka listener methods found on bean type.")
+				.withRootCauseInstanceOf(IllegalStateException.class)
+				.withMessageContaining("No Kafka listener methods in bean:")
 				.withMessageContaining("NoHandlerMethodListener");
 
 	}