template.newMessage(msg)
    .withMessageCustomizer((mb) -> mb.key("foo-msg-key"))
    .send();

template.newMessage(msg)
    .withProducerCustomizer((pb) -> pb.enableChunking(true).enableBatching(false))
    .send();

template.newMessage(msg)
    .withProducerCustomizer((pb) -> pb.messageRouter(messageRouter))
    .send();

template.newMessage(msg)
    .withProducerCustomizer((pb) -> pb.intercept(interceptor))
    .send();

void sendUser() {
    var user = randomUser();
    template.newMessage(user)
        .withTopic("user-topic")
        .withProducerCustomizer((b) -> b.producerName("user"))
        .send();
}

void sendUser() {
    var user = randomUser();
    var name = randomName();
    template.newMessage(user)
        .withTopic("user-topic")
        .withProducerCustomizer((b) -> b.producerName(name))
        .send();
}

void sendUser() {
    var user = randomUser();
    template.newMessage(user)
        .withTopic("user-topic")
        .withProducerCustomizer((b) -> {
           var name = SomeHelper.someStaticMethod();
           b.producerName(name);
        })
        .send();
}

@PulsarListener(topics = "my-generic-topic", schemaType = SchemaType.AUTO_CONSUME)
void listen(org.apache.pulsar.client.api.Message<GenericRecord> message) {
    GenericRecord record = message.getValue();
    record.getFields().forEach((f) ->
            System.out.printf("%s = %s%n", f.getName(), record.getField(f)));
}

@PulsarListener(topics = "hello-topic", consumerCustomizer = "myCustomizer")
public void listen(String message) {
    System.out.println("Message Received: " + message);
}

@Bean
PulsarListenerConsumerBuilderCustomizer<String> myCustomizer() {
    return (builder) -> builder.consumerName("myConsumer");
}

public DefaultPulsarMessageListenerContainer(PulsarConsumerFactory<? super T> pulsarConsumerFactory,
			PulsarContainerProperties pulsarContainerProperties)
}

public PulsarContainerProperties(String... topics)

public PulsarContainerProperties(Pattern topicPattern)

Map<String, Object> config = new HashMap<>();
config.put("topics", "my-topic");
PulsarConsumerFactory<String> pulsarConsumerFactorY = DefaultPulsarConsumerFactory<>(pulsarClient, config);

PulsarContainerProperties pulsarContainerProperties = new PulsarContainerProperties();

pulsarContainerProperties.setMessageListener((PulsarRecordMessageListener<?>) (consumer, msg) -> {
		});

DefaultPulsarMessageListenerContainer<String> pulsarListenerContainer = new DefaultPulsarMessageListenerContainer(pulsarConsumerFacotyr,
        pulsarContainerProperties);

return pulsarListenerContainer;

public ConcurrentPulsarMessageListenerContainer(PulsarConsumerFactory<? super T> pulsarConsumerFactory,
    PulsarContainerProperties pulsarContainerProperties)

@PulsarListener(topics = "my-topic", subscriptionName = "subscription-1",
				subscriptionType = SubscriptionType.Failover, concurrency = "3")
void listen(String message, Consumer<String> consumer) {
    ...
    System.out.println("Current Thread: " + Thread.currentThread().getName());
    System.out.println("Current Consumer: " + consumer.getConsumerName());
}

@PulsarListener(topics = "my-topic", subscriptionName = "subscription-1",
				subscriptionType = SubscriptionType.Shared, concurrency = "5")
void listen(String message) {
    ...
}

@PulsarListener(subscriptionName = "hello-pulsar-subscription", topics = "hello-pulsar")
public void listen(String message) {
    System.out.println("Message Received: " + message);
}

@PulsarListener(subscriptionName = "hello-batch-subscription", topics = "hello-batch", schemaType = SchemaType.JSON, batch = true)
public void listen4(List<Foo> messages) {
    System.out.println("records received :" + messages.size());
    messages.forEach((message) -> System.out.println("record : " + message));
}

@PulsarListener(topics = "simpleListenerWithHeaders")
void simpleListenerWithHeaders(String data, @Header(PulsarHeaders.MESSAGE_ID) MessageId messageId,
                @Header(PulsarHeaders.RAW_DATA) byte[] rawData,
                @Header("foo") String foo) {

}

@PulsarListener(topics = "simpleBatchListenerWithHeaders", batch = true)
void simpleBatchListenerWithHeaders(List<String> data,
					@Header(PulsarHeaders.MESSAGE_ID) List<MessageId> messageIds,
					@Header(PulsarHeaders.TOPIC_NAME) List<String> topicNames, @Header("foo") List<String> fooValues) {

}

@PulsarListener(subscriptionName = "hello-pulsar-subscription", topics = "hello-pulsar")
public void listen(String message) {
    System.out.println("Message Received: " + message);
}

@PulsarListener(subscriptionName = "hello-pulsar-subscription", topics = "hello-pulsar", ackMode = AckMode.RECORD)
public void listen(String message) {
    System.out.println("Message Received: " + message);
}

@PulsarListener(subscriptionName = "hello-pulsar-subscription", topics = "hello-pulsar", ackMode = AckMode.MANUAL)
public void listen(Message<String> message, Acknowledgment acknowledgment) {
    System.out.println("Message Received: " + message.getValue());
	acknowledgment.acknowledge();
}

void acknowledge();

void acknowledge(MessageId messageId);

void acknowledge(List<MessageId> messageIds);

void nack();

void nack(MessageId messageId);

@PulsarListener(subscriptionName = "hello-pulsar-subscription", topics = "hello-pulsar", ackMode = AckMode.MANUAL)
public void listen(Message<String> message, Consumer<String> consumer) {
    System.out.println("Message Received: " + message.getValue());
	try {
		consumer.acknowledge(message);
	}
	catch (Exception e) {
		....
	}
}

@PulsarListener(subscriptionName = "hello-pulsar-subscription", topics = "hello-pulsar", batch = true)
public void batchListen(List<Foo> messages) {
    for (Foo foo : messages) {
		...
    }
}

void acknowledge();

void acknowledge(MessageId messageId);

void acknowledge(List<MessageId> messageIds);

void nack();

void nack(MessageId messageId);

@PulsarListener(subscriptionName = "hello-pulsar-subscription", topics = "hello-pulsar")
public void listen(List<Message<String>> messgaes, Acknowlegement acknowledgment) {
    for (Message<String> message : messages) {
		try {
			...
	        acknowledgment.acknowledge(message.getMessageId());
		}
		catch (Exception e) {
			acknowledgment.nack(message.getMessageId());
		}
    }
}

@PulsarListener(subscriptionName = "subscription-1", topics = "topic-1"
                properties = {"ackTimeout=60s"})
public void listen(String s) {
    ...
}

@EnablePulsar
@Configuration
class AckTimeoutRedeliveryConfig {

    @PulsarListener(subscriptionName = "withAckTimeoutRedeliveryBackoffSubscription",
            topics = "withAckTimeoutRedeliveryBackoff-test-topic",
            ackTimeoutRedeliveryBackoff = "ackTimeoutRedeliveryBackoff",
            properties = { "ackTimeout=60s" })
    void listen(String msg) {
        // some long-running process that may cause an ack timeout
    }

    @Bean
    RedeliveryBackoff ackTimeoutRedeliveryBackoff() {
        return MultiplierRedeliveryBackoff.builder().minDelayMs(1000).maxDelayMs(10 * 1000).multiplier(2)
                .build();
    }

}

@PulsarListener(subscriptionName = "subscription-1", topics = "topic-1"
                properties = {"negativeAckRedeliveryDelay=10ms"})
public void listen(String s) {
    ...
}

@EnablePulsar
@Configuration
class NegativeAckRedeliveryConfig {

    @PulsarListener(subscriptionName = "withNegRedeliveryBackoffSubscription",
            topics = "withNegRedeliveryBackoff-test-topic", negativeAckRedeliveryBackoff = "redeliveryBackoff",
            subscriptionType = SubscriptionType.Shared)
    void listen(String msg) {
        throw new RuntimeException("fail " + msg);
    }

    @Bean
    RedeliveryBackoff redeliveryBackoff() {
        return MultiplierRedeliveryBackoff.builder().minDelayMs(1000).maxDelayMs(10 * 1000).multiplier(2)
                .build();
    }

}

@EnablePulsar
@Configuration
class DeadLetterPolicyConfig {

    @PulsarListener(id = "deadLetterPolicyListener", subscriptionName = "deadLetterPolicySubscription",
            topics = "topic-with-dlp", deadLetterPolicy = "deadLetterPolicy",
            subscriptionType = SubscriptionType.Shared, properties = { "ackTimeout=1s" })
    void listen(String msg) {
        throw new RuntimeException("fail " + msg);
    }

    @PulsarListener(id = "dlqListener", topics = "my-dlq-topic")
    void listenDlq(String msg) {
        System.out.println("From DLQ: " + msg);
    }

    @Bean
    DeadLetterPolicy deadLetterPolicy() {
        return DeadLetterPolicy.builder().maxRedeliverCount(10).deadLetterTopic("my-dlq-topic").build();
    }

}

@EnablePulsar
@Configuration
class PulsarConsumerErrorHandlerConfig {

    @Bean
    PulsarConsumerErrorHandler<String> pulsarConsumerErrorHandler(
            PulsarTemplate<String> pulsarTemplate) {
        return new DefaultPulsarConsumerErrorHandler<>(
                new PulsarDeadLetterPublishingRecoverer<>(pulsarTemplate, (c, m) -> "my-foo-dlt"), new FixedBackOff(100, 10));
    }

    @PulsarListener(id = "pulsarConsumerErrorHandler-id", subscriptionName = "pulsatConsumerErrorHandler-subscription",
                    topics = "pulsarConsumerErrorHandler-topic",
					pulsarConsumerErrorHandler = "pulsarConsumerErrorHandler")
    void listen(String msg) {
        throw new RuntimeException("fail " + msg);
    }

    @PulsarListener(id = "pceh-dltListener", topics = "my-foo-dlt")
    void listenDlt(String msg) {
        System.out.println("From DLT: " + msg);
    }

}

@FunctionalInterface
public interface PulsarMessageRecovererFactory<T> {

	/**
	 * Provides a message recoverer {@link PulsarMessageRecoverer}.
	 * @param consumer Pulsar consumer
	 * @return {@link PulsarMessageRecoverer}.
	 */
	PulsarMessageRecoverer<T> recovererForConsumer(Consumer<T> consumer);

}

public interface PulsarMessageRecoverer<T> {

	/**
	 * Recover a failed message, for e.g. send the message to a DLT.
	 * @param message Pulsar message
	 * @param exception exception from failed message
	 */
	void recoverMessage(Message<T> message, Exception exception);

}

@Bean
PulsarConsumerErrorHandler<Integer> pulsarConsumerErrorHandler(PulsarClient pulsarClient) {
    PulsarProducerFactory<Integer> pulsarProducerFactory = new DefaultPulsarProducerFactory<>(pulsarClient, Map.of());
        PulsarTemplate<Integer> pulsarTemplate = new PulsarTemplate<>(pulsarProducerFactory);

        BiFunction<Consumer<?>, Message<?>, String> destinationResolver =
                (c, m) -> "my-foo-dlt";

        PulsarDeadLetterPublishingRecoverer<Integer> pulsarDeadLetterPublishingRecoverer =
                new PulsarDeadLetterPublishingRecoverer<>(pulsarTemplate, destinationResolver);

        return new DefaultPulsarConsumerErrorHandler<>(pulsarDeadLetterPublishingRecoverer,
                new FixedBackOff(100, 5));
}

@PulsarListener(subscriptionName = "batch-demo-5-sub", topics = "batch-demo-4", batch = true, concurrency = "3",
            subscriptionType = SubscriptionType.Failover,
            pulsarConsumerErrorHandler = "pulsarConsumerErrorHandler", ackMode = AckMode.MANUAL)
void listen(List<Message<Integer>> data, Consumer<Integer> consumer, Acknowledgment acknowledgment) {
    for (Message<Integer> datum : data) {
        if (datum.getValue() == 5) {
            throw new PulsarBatchListenerFailedException("failed", datum);
        }
        acknowledgement.acknowledge(datum.getMessageId());
    }
}

@Bean
PulsarConsumerErrorHandler<String> pulsarConsumerErrorHandler(
        PulsarTemplate<String> pulsarTemplate) {
    return new DefaultPulsarConsumerErrorHandler<>(
            new PulsarDeadLetterPublishingRecoverer<>(pulsarTemplate, (c, m) -> "my-foo-dlt"), new FixedBackOff(100, 10));
}

@PulsarListener(subscriptionName = "my-dlt-subscription", topics = "my-foo-dlt")
void dltReceiver(Message<Integer> message) {
    System.out.println("DLT - RECEIVED: " + message.getValue());
}

@PulsarReader(id = "reader-demo-id", topics = "reader-demo-topic", startMessageId = "earliest")
void read(String message) {
    //...
}

@PulsarReader(id = "reader-customizer-demo-id", topics = "reader-customizer-demo-topic",
    readerCustomizer = "myCustomizer")
void read(String message) {
    //...
}

@Bean
public PulsarReaderReaderBuilderCustomizer<String> myCustomizer() {
    return readerBuilder -> {
        readerBuilder.startMessageId(messageId); // the first message read is after this message id.
        // Any other customizations on the readerBuilder
    };
}