SenderConfig.java

@Configuration
@EnableKafka
public class SenderConfig {

    @Value("${spring.kafka.bootstrap-servers}")
    private String bootstrapServers;

    @Bean
    public Map<String, Object> producerConfigs() {

        Map<String, Object> props = new HashMap<>();
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JsonSerializer.class);

        return props;
    }

    @Bean
    public ProducerFactory<String, CustomerChangeEvent> producerFactory() {

        return new DefaultKafkaProducerFactory<>(producerConfigs());
    }

    @Bean
    public KafkaTemplate<String, CustomerChangeEvent> kafkaTemplate() {

        return new KafkaTemplate<>(producerFactory());
    }

    @Bean
    public Sender sender() {

        return new Sender();
    }
}