* add @nullable at AbstractKafkaListenerEndpoint.setGroupId

* change `KafkaListenerEndpointDescriptor` type to `record` at `KafkaListenerEndpointRegistrar`
* cleanup `KafkaListenerEndpointRegistry`
* change `collect(Collectors.toList())` to `toList()` at `EndpointCustomizerFactory`.
* cleanup `EndpointHandlerMethod`.
* cleanup tests.

Author: Wzy19930507

spring-kafka/src/main/java/org/springframework/kafka/config/AbstractKafkaListenerEndpoint.java

@@ -176,7 +176,7 @@ public String getId() {
 	 * @param groupId the group id.
 	 * @since 1.3
 	 */
-	public void setGroupId(String groupId) {
+	public void setGroupId(@Nullable String groupId) {
 		this.groupId = groupId;
 	}
 

spring-kafka/src/main/java/org/springframework/kafka/config/KafkaListenerEndpointRegistrar.java

@@ -256,19 +256,16 @@ public void registerEndpoint(KafkaListenerEndpoint endpoint) {
 	}
 
 
-	private static final class KafkaListenerEndpointDescriptor {
+	private record KafkaListenerEndpointDescriptor(KafkaListenerEndpoint endpoint,
+				KafkaListenerContainerFactory<?> containerFactory) {
 
-		private final KafkaListenerEndpoint endpoint;
+			private KafkaListenerEndpointDescriptor(KafkaListenerEndpoint endpoint,
+					@Nullable KafkaListenerContainerFactory<?> containerFactory) {
 
-		private final KafkaListenerContainerFactory<?> containerFactory;
-
-		private KafkaListenerEndpointDescriptor(KafkaListenerEndpoint endpoint,
-				@Nullable KafkaListenerContainerFactory<?> containerFactory) {
+				this.endpoint = endpoint;
+				this.containerFactory = containerFactory;
+			}
 
-			this.endpoint = endpoint;
-			this.containerFactory = containerFactory;
 		}
 
-	}
-
 }

spring-kafka/src/main/java/org/springframework/kafka/config/KafkaListenerEndpointRegistry.java

@@ -66,6 +66,7 @@
  * @author Artem Bilan
  * @author Gary Russell
  * @author Asi Bross
+ * @author Wang Zhiyang
  *
  * @see KafkaListenerEndpoint
  * @see MessageListenerContainer
@@ -94,8 +95,8 @@ public class KafkaListenerEndpointRegistry implements ListenerContainerRegistry,
 
 	@Override
 	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
-		if (applicationContext instanceof ConfigurableApplicationContext) {
-			this.applicationContext = (ConfigurableApplicationContext) applicationContext;
+		if (applicationContext instanceof ConfigurableApplicationContext cac) {
+			this.applicationContext = cac;
 		}
 	}
 
@@ -170,8 +171,7 @@ public Collection<MessageListenerContainer> getListenerContainers() {
 	 */
 	@Override
 	public Collection<MessageListenerContainer> getAllListenerContainers() {
-		List<MessageListenerContainer> containers = new ArrayList<>();
-		containers.addAll(getListenerContainers());
+		List<MessageListenerContainer> containers = new ArrayList<>(getListenerContainers());
 		refreshContextContainers();
 		containers.addAll(this.unregisteredContainers.values());
 		return containers;
@@ -232,7 +232,7 @@ public void registerListenerContainer(KafkaListenerEndpoint endpoint, KafkaListe
 					group = appContext.getBean(groupName + ".group", ContainerGroup.class);
 				}
 				else {
-					containerGroup = new ArrayList<MessageListenerContainer>();
+					containerGroup = new ArrayList<>();
 					appContext.getBeanFactory().registerSingleton(groupName, containerGroup); // NOSONAR - hasText
 					group = new ContainerGroup(groupName);
 					appContext.getBeanFactory().registerSingleton(groupName + ".group", group);
@@ -274,21 +274,19 @@ public MessageListenerContainer unregisterListenerContainer(String id) {
 	protected MessageListenerContainer createListenerContainer(KafkaListenerEndpoint endpoint,
 			KafkaListenerContainerFactory<?> factory) {
 
-		if (endpoint instanceof MethodKafkaListenerEndpoint) {
-			MethodKafkaListenerEndpoint<?, ?> mkle = (MethodKafkaListenerEndpoint<?, ?>) endpoint;
+		if (endpoint instanceof MethodKafkaListenerEndpoint<?, ?> mkle) {
 			Object bean = mkle.getBean();
-			if (bean instanceof EndpointHandlerMethod) {
-				EndpointHandlerMethod ehm = (EndpointHandlerMethod) bean;
+			if (bean instanceof EndpointHandlerMethod ehm) {
 				ehm = new EndpointHandlerMethod(ehm.resolveBean(this.applicationContext), ehm.getMethodName());
 				mkle.setBean(ehm.resolveBean(this.applicationContext));
 				mkle.setMethod(ehm.getMethod());
 			}
 		}
 		MessageListenerContainer listenerContainer = factory.createListenerContainer(endpoint);
 
-		if (listenerContainer instanceof InitializingBean) {
+		if (listenerContainer instanceof InitializingBean initializingBean) {
 			try {
-				((InitializingBean) listenerContainer).afterPropertiesSet();
+				initializingBean.afterPropertiesSet();
 			}
 			catch (Exception ex) {
 				throw new BeanInitializationException("Failed to initialize message listener container", ex);
@@ -324,11 +322,6 @@ public int getPhase() {
 		return this.phase;
 	}
 
-	@Override
-	public boolean isAutoStartup() {
-		return true;
-	}
-
 	@Override
 	public void start() {
 		for (MessageListenerContainer listenerContainer : getListenerContainers()) {

spring-kafka/src/main/java/org/springframework/kafka/retrytopic/EndpointCustomizerFactory.java

@@ -19,7 +19,6 @@
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import org.springframework.beans.factory.BeanFactory;
@@ -124,7 +123,7 @@ protected Collection<EndpointCustomizer.TopicNamesHolder> customizeAndRegisterTo
 		return getTopics(endpoint)
 				.stream()
 				.map(topic -> new EndpointCustomizer.TopicNamesHolder(topic, namesProvider.getTopicName(topic)))
-				.collect(Collectors.toList());
+				.toList();
 	}
 
 	private Collection<String> getTopics(MethodKafkaListenerEndpoint<?, ?> endpoint) {
@@ -135,7 +134,7 @@ private Collection<String> getTopics(MethodKafkaListenerEndpoint<?, ?> endpoint)
 				topics = Arrays.stream(topicPartitionsToAssign)
 						.map(TopicPartitionOffset::getTopic)
 						.distinct()
-						.collect(Collectors.toList());
+						.toList();
 			}
 		}
 

spring-kafka/src/main/java/org/springframework/kafka/support/EndpointHandlerMethod.java

@@ -32,6 +32,8 @@
  *
  * @author Tomaz Fernandes
  * @author Gary Russell
+ * @author Wang Zhiyang
+ *
  * @since 2.7
  *
  */
@@ -66,15 +68,15 @@ public EndpointHandlerMethod(Object bean, Method method) {
 	 * @return the method.
 	 */
 	public Method getMethod() {
-		if (this.beanOrClass instanceof Class) {
-			return forClass((Class<?>) this.beanOrClass);
+		if (this.beanOrClass instanceof Class<?> clazz) {
+			return forClass(clazz);
 		}
 		Assert.state(this.bean != null, "Bean must be resolved before accessing its method");
 		if (this.bean instanceof EndpointHandlerMethod) {
 			try {
 				return Object.class.getMethod("toString");
 			}
-			catch (NoSuchMethodException | SecurityException e) {
+			catch (NoSuchMethodException | SecurityException ignored) {
 			}
 		}
 		return forClass(this.bean.getClass());
@@ -91,13 +93,12 @@ public String getMethodName() {
 	}
 
 	public Object resolveBean(BeanFactory beanFactory) {
-		if (this.bean instanceof EndpointHandlerMethod) {
-			return ((EndpointHandlerMethod) this.bean).beanOrClass;
+		if (this.bean instanceof EndpointHandlerMethod endpointHandlerMethod) {
+			return endpointHandlerMethod.beanOrClass;
 		}
 		if (this.bean == null) {
 			try {
-				if (this.beanOrClass instanceof Class) {
-					Class<?> clazz = (Class<?>) this.beanOrClass;
+				if (this.beanOrClass instanceof Class<?> clazz) {
 					try {
 						this.bean = beanFactory.getBean(clazz);
 					}

spring-kafka/src/test/java/org/springframework/kafka/retrytopic/RetryTopicConfigurationProviderTests.java

@@ -47,6 +47,8 @@
  * @author Tomaz Fernandes
  * @author Gary Russell
  * @author Fabio da Silva Jr.
+ * @author Wang Zhiyang
+ *
  * @since 2.7
  */
 @ExtendWith(MockitoExtension.class)
@@ -56,9 +58,7 @@ class RetryTopicConfigurationProviderTests {
 
 	{
 		this.beanFactory = mock(ConfigurableListableBeanFactory.class);
-		willAnswer(invoc -> {
-			return invoc.getArgument(0);
-		}).given(this.beanFactory).resolveEmbeddedValue(anyString());
+		willAnswer(invoc -> invoc.getArgument(0)).given(this.beanFactory).resolveEmbeddedValue(anyString());
 	}
 
 	private final String[] topics = {"topic1", "topic2"};
@@ -81,18 +81,12 @@ private Method getAnnotatedMethod(String methodName) {
 	@Mock
 	Object bean;
 
-	@Mock
-	RetryableTopic annotation;
-
 	@Mock
 	KafkaOperations<?, ?> kafkaOperations;
 
 	@Mock
 	RetryTopicConfiguration retryTopicConfiguration;
 
-	@Mock
-	RetryTopicConfiguration retryTopicConfiguration2;
-
 	@Test
 	void shouldProvideFromAnnotation() {
 

spring-kafka/src/test/java/org/springframework/kafka/retrytopic/RetryTopicConfigurationSupportTests.java

@@ -185,7 +185,6 @@ void testCreateBackOffManager() {
 				ContainerPartitionPausingBackOffManagerFactory.class);
 		KafkaConsumerBackoffManager backoffManagerMock = mock(KafkaConsumerBackoffManager.class);
 		TaskScheduler taskSchedulerMock = mock(TaskScheduler.class);
-		Clock clock = mock(Clock.class);
 		ApplicationContext ctx = mock(ApplicationContext.class);
 		given(componentFactory.kafkaBackOffManagerFactory(registry, ctx)).willReturn(factory);
 		given(factory.create()).willReturn(backoffManagerMock);

spring-kafka/src/test/java/org/springframework/kafka/retrytopic/RetryTopicConfigurerTests.java

@@ -294,15 +294,6 @@ private void assertTopicNames(String retrySuffix, DestinationTopic.Properties de
 		assertThat(retryTopicName.get(index + 1)).isEqualTo(secondTopicName);
 	}
 
-	private void thenAssertEndpointProcessing(MethodKafkaListenerEndpoint<?, ?> endpoint) {
-		then(endpoint).should(times(1)).setTopics(topics.toArray(new String[]{}));
-		then(endpoint).should(times(1)).setId("testId");
-		then(endpoint).should(times(1)).setGroup("testGroup");
-		then(endpoint).should(times(1)).setGroupId("testGroupId");
-		then(endpoint).should(times(1)).setClientIdPrefix("testClientPrefix");
-		then(endpoint).should(times(1)).setBeanFactory(defaultListableBeanFactory);
-	}
-
 	public void noOpsMethod() {
 		// noOps
 	}
@@ -349,7 +340,6 @@ void shouldInstantiateIfNotInContainer() {
 
 	@LogLevels(classes = RetryTopicConfigurer.class, level = "info")
 	@Test
-	@SuppressWarnings("deprecation")
 	void shouldLogConsumerRecordMessage() {
 		RetryTopicConfigurer.LoggingDltListenerHandlerMethod method =
 				new RetryTopicConfigurer.LoggingDltListenerHandlerMethod();

spring-kafka/src/test/java/org/springframework/kafka/retrytopic/RetryTopicExceptionRoutingIntegrationTests.java

@@ -332,7 +332,6 @@ public RetryTopicConfiguration blockingAndTopic(KafkaTemplate<String, String> te
 		}
 
 		@Bean
-		@SuppressWarnings("deprecation")
 		public RetryTopicConfiguration onlyTopic(KafkaTemplate<String, String> template) {
 			return RetryTopicConfigurationBuilder
 					.newInstance()