From 36e16a4c60f4af79aa189545d13f10a604bf3ae5 Mon Sep 17 00:00:00 2001
From: ChickenchickenLove <ojt90902@naver.com>
Date: Wed, 30 Apr 2025 00:47:54 +0900
Subject: [PATCH] GH-3869: Fail if no `@KafkaHandler` on class-level
 `@KafkaListener`

Fixes: #3869
Issue link: https://github.com/spring-projects/spring-kafka/issues/3869

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

Signed-off-by: ChickenchickenLove <ojt90902@naver.com>
Co-authored-by: Artem Bilan <artem.bilan@broadcom.com>
(cherry picked from commit 6682837501d81866d8aad9804160c9035bf99f84)
---
 ...kaListenerAnnotationBeanPostProcessor.java |  5 ++
 ...tenerAnnotationBeanPostProcessorTests.java | 64 +++++++++++++++++++
 2 files changed, 69 insertions(+)
 create mode 100644 spring-kafka/src/test/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessorTests.java

diff --git a/spring-kafka/src/main/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessor.java b/spring-kafka/src/main/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessor.java
index dcaafc4b..abd5c7b1 100644
--- a/spring-kafka/src/main/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessor.java
+++ b/spring-kafka/src/main/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessor.java
@@ -414,6 +414,11 @@ public class KafkaListenerAnnotationBeanPostProcessor<K, V>
 					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);
 				}
diff --git a/spring-kafka/src/test/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessorTests.java b/spring-kafka/src/test/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessorTests.java
new file mode 100644
index 00000000..af2a9e08
--- /dev/null
+++ b/spring-kafka/src/test/java/org/springframework/kafka/annotation/KafkaListenerAnnotationBeanPostProcessorTests.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.kafka.annotation;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.BeanCreationException;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.stereotype.Component;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+
+/**
+ * @author Sanghyeok An
+ *
+ * @since 4.0.0
+ */
+
+class KafkaListenerAnnotationBeanPostProcessorTests {
+
+	@Test
+	void ctx_should_be_fail_to_register_bean_when_no_listener_methods_exist() {
+
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.register(TestConfig.class);
+
+		assertThatExceptionOfType(BeanCreationException.class)
+				.isThrownBy(ctx::refresh)
+				.withRootCauseInstanceOf(IllegalStateException.class)
+				.withMessageContaining("No Kafka listener methods in bean:")
+				.withMessageContaining("NoHandlerMethodListener");
+
+	}
+
+	@EnableKafka
+	@Configuration
+	static class TestConfig {
+
+		@Component
+		@KafkaListener
+		static class NoHandlerMethodListener {
+
+			public void listen(String message) {
+			}
+		}
+
+	}
+
+}