Polish "Improve Kafka Auto-configuration"

Closes gh-14215

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

@@ -78,7 +78,7 @@ public class ConcurrentKafkaListenerContainerFactoryConfigurer {
 	 * Set the {@link KafkaAwareTransactionManager} to use.
 	 * @param transactionManager the transaction manager
 	 */
-	public void setTransactionManager(
+	void setTransactionManager(
 			KafkaAwareTransactionManager<Object, Object> transactionManager) {
 		this.transactionManager = transactionManager;
 	}
@@ -87,7 +87,7 @@ public class ConcurrentKafkaListenerContainerFactoryConfigurer {
 	 * Set the {@link ErrorHandler} to use.
 	 * @param errorHandler the error handler
 	 */
-	public void setErrorHandler(ErrorHandler errorHandler) {
+	void setErrorHandler(ErrorHandler errorHandler) {
 		this.errorHandler = errorHandler;
 	}
 
@@ -95,7 +95,7 @@ public class ConcurrentKafkaListenerContainerFactoryConfigurer {
 	 * Set the {@link AfterRollbackProcessor} to use.
 	 * @param afterRollbackProcessor the after rollback processor
 	 */
-	public void setAfterRollbackProcessor(
+	void setAfterRollbackProcessor(
 			AfterRollbackProcessor<Object, Object> afterRollbackProcessor) {
 		this.afterRollbackProcessor = afterRollbackProcessor;
 	}

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

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -75,8 +75,8 @@ class KafkaAnnotationDrivenConfiguration {
 		configurer.setKafkaProperties(this.properties);
 		configurer.setMessageConverter(this.messageConverter);
 		configurer.setReplyTemplate(this.kafkaTemplate);
-		configurer.setErrorHandler(this.errorHandler);
 		configurer.setTransactionManager(this.transactionManager);
+		configurer.setErrorHandler(this.errorHandler);
 		configurer.setAfterRollbackProcessor(this.afterRollbackProcessor);
 		return configurer;
 	}

spring-boot-project/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -5628,18 +5628,6 @@ When the Apache Kafka infrastructure is present, any bean can be annotated with
 `@KafkaListener` to create a listener endpoint. If no `KafkaListenerContainerFactory` has
 been defined, a default one is automatically configured with keys defined in
 `spring.kafka.listener.*`.
-If the property `spring.kafka.producer.transaction-id-prefix` is defined, a
-`KafkaTransactionManager` will be auto-configured with name `kafkaTransactionManager` and
-will be wired into the container factory.
-Also, if `RecordMessageConverter`, `ErrorHandler` and/or
-`AfterRollbackProcessor` beans are defined, they are automatically associated to the
-default factory.
-
-IMPORTANT: The auto configuration of these beans occur if there is just a single
-instance.
-When using a `ChainedKafkaTransactionManager`, it will usually reference the configured
-`KafkaTransactionManager` bean, so the chained manager must be marked
-`@Primary` if you want it wired into the container factory.
 
 The following component creates a listener endpoint on the `someTopic` topic:
 
@@ -5656,6 +5644,16 @@ The following component creates a listener endpoint on the `someTopic` topic:
 	}
 ----
 
+If a `KafkaTransactionManager` bean is defined, it is automatically associated to the
+container factory. Similarly, if a `RecordMessageConverter`, `ErrorHandler` or
+`AfterRollbackProcessor` bean is defined, it is automatically associated to the default
+factory.
+
+TIP: A custom `ChainedKafkaTransactionManager` must be marked `@Primary` as it usually
+reference the auto-configured `KafkaTransactionManager` bean.
+
+
+
 [[boot-features-kafka-streams]]
 ==== Kafka Streams
 Spring for Apache Kafka provides a factory bean to create a `StreamsBuilder` object and