Polish "Use BatchErrorHandler when Kafka listener type is batch"

Closes gh-16499

Author: snicoll

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

@@ -98,7 +98,7 @@ void setErrorHandler(ErrorHandler errorHandler) {
 	 * Set the {@link BatchErrorHandler} to use.
 	 * @param batchErrorHandler the error handler
 	 */
-	public void setBatchErrorHandler(BatchErrorHandler batchErrorHandler) {
+	void setBatchErrorHandler(BatchErrorHandler batchErrorHandler) {
 		this.batchErrorHandler = batchErrorHandler;
 	}
 
@@ -133,15 +133,14 @@ private void configureListenerFactory(
 		map.from(properties::getConcurrency).to(factory::setConcurrency);
 		map.from(this.messageConverter).to(factory::setMessageConverter);
 		map.from(this.replyTemplate).to(factory::setReplyTemplate);
-		map.from(properties::getType).whenEqualTo(Listener.Type.BATCH)
-				.toCall(() -> factory.setBatchListener(true));
-		map.from(this.afterRollbackProcessor).to(factory::setAfterRollbackProcessor);
 		if (properties.getType().equals(Listener.Type.BATCH)) {
+			factory.setBatchListener(true);
 			factory.setBatchErrorHandler(this.batchErrorHandler);
 		}
 		else {
 			factory.setErrorHandler(this.errorHandler);
 		}
+		map.from(this.afterRollbackProcessor).to(factory::setAfterRollbackProcessor);
 	}
 
 	private void configureContainer(ContainerProperties container) {