Update documentation

spring-batch-docs/asciidoc/appendix.adoc

@@ -27,6 +27,9 @@
 |AmqpItemReader|Given a Spring `AmqpTemplate`, it provides
             synchronous receive methods. The `receiveAndConvert()` method
             lets you receive POJO objects.
+|KafkaItemReader|An `ItemReader` that reads messages from an Apache Kafka topic.
+It can be configured to read messages from multiple partitions of the same topic.
+This reader stores message offsets in the execution context to support restart capabilities.
 |FlatFileItemReader|Reads from a flat file. Includes `ItemStream`
             and `Skippable` functionality. See link:readersAndWriters.html#flatFileItemReader[`FlatFileItemReader`].
 |HibernateCursorItemReader|Reads from a cursor based on an HQL query. See

spring-batch-docs/asciidoc/readersAndWriters.adoc

@@ -3054,6 +3054,7 @@ Spring Batch offers the following readers and writers for commonly used messagin
 * <<amqpItemWriter>>
 * <<jmsItemReader>>
 * <<jmsItemWriter>>
+* <<kafkaItemReader>>
 * <<kafkaItemWriter>>
 
 [[amqpItemReader]]
@@ -3082,6 +3083,13 @@ The `JmsItemWriter` is an `ItemWriter` for JMS that uses a `JmsTemplate`. The te
 should have a default destination, which is used to send items in `write(List)`. Spring
 Batch provides a `JmsItemWriterBuilder` to construct an instance of the `JmsItemWriter`.
 
+[[kafkaItemReader]]
+===== `KafkaItemReader`
+The `KafkaItemReader` is an `ItemReader` for an Apache Kafka topic. It can be configured
+to read messages from multiple partitions of the same topic. It stores message offsets
+in the execution context to support restart capabilities. Spring Batch provides a
+`KafkaItemReaderBuilder` to construct an instance of the `KafkaItemReader`.
+
 [[kafkaItemWriter]]
 ===== `KafkaItemWriter`
 The `KafkaItemWriter` is an `ItemWriter` for Apache Kafka that uses a `KafkaTemplate` to

spring-batch-docs/asciidoc/whatsnew.adoc

@@ -9,6 +9,7 @@
 Spring Batch 4.2 adds the following features:
 
 * Support for batch metrics with https://micrometer.io[Micrometer]
+* Support for reading/writing data from/to https://kafka.apache.org[Apache Kafka] topics
 * Improved documentation
 
 [[whatsNewMetrics]]
@@ -24,6 +25,13 @@ supported by Micrometer.
 For more details about this feature, please refer to the
 <<monitoring-and-metrics.adoc#monitoring-and-metrics,Monitoring and metrics>> chapter.
 
+[[whatsNewKafka]]
+=== Apache Kafka item reader/writer
+
+This release adds a new `KafkaItemReader` and `KafkaItemWriter` to read data from and
+write it to Kafka topics. For more details about these new components, please refer
+to the https://docs.spring.io/spring-batch/4.2.x/api/index.html[Javadoc].
+
 [[whatsNewDocs]]
 === Documentation updates