[Module README](../README.md) · [Producing →](02-producing.md)

# 1. The on-ramp, and the dependency that is not the one you remember

Under Spring Boot 3 you added `org.springframework.kafka:spring-kafka` and got a
`KafkaTemplate`. Under Boot 4 you get this:

```
No qualifying bean of type 'org.springframework.kafka.core.KafkaTemplate<java.lang.String,
com.ankurm.kafkabasics.OrderEvent>' available
```

Boot 4 split the auto-configurations out of `spring-boot-autoconfigure` into per-technology
modules. Kafka's now lives in `spring-boot-kafka`, package
`org.springframework.boot.kafka.autoconfigure`, and a bare `spring-kafka` dependency does not
bring it. The application compiles, the context starts, and there is simply no template.

```xml
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-kafka</artifactId>
</dependency>
```

That is the fix, and the same shape applies elsewhere: `spring-boot-starter-amqp` for RabbitMQ,
`spring-boot-starter-restclient` for `RestClient.Builder`. The rule of thumb for Boot 4 is that
if you are depending on a library directly rather than through a Boot starter, you are probably
missing its auto-configuration.

## What the starter actually gives you

| Bean | Comes from | Notes |
|---|---|---|
| `KafkaTemplate<?, ?>` | `KafkaAutoConfiguration` | typed by your injection point |
| `ProducerFactory` / `ConsumerFactory` | `KafkaAutoConfiguration` | built from `spring.kafka.*` |
| `KafkaListenerContainerFactory` | `KafkaAnnotationDrivenConfiguration` | what `@KafkaListener` binds to |
| `KafkaAdmin` | `KafkaAutoConfiguration` | creates `NewTopic` beans at startup |

`KafkaAdmin` is worth knowing about early: declare a `NewTopic` bean and Boot creates the topic
on startup with the partition count and replication factor you asked for. It will **not** change
an existing topic's partition count, so a `NewTopic` bean that disagrees with the cluster is
silently ignored rather than applied.

## Versions

Boot 4.1.1 manages Spring Kafka **4.1.1** and kafka-clients **4.2.1**. Note the second one:
Maven Central has kafka-clients 4.3.1, and overriding the managed version to reach it is the
kind of change that works until it does not. Let the BOM decide.

[Producing &rarr;](02-producing.md)