AWS SDK for Java 2.x - Messaging (SQS & SNS)

Overview

Provides patterns for SQS queues and SNS topics with AWS SDK for Java 2.x: client setup, queue management, message operations, subscriptions, and Spring Boot integration.

When to Use

Setting up SQS queues (standard or FIFO) for message buffering
Implementing pub/sub with SNS topics and subscriptions
Processing messages from SQS queues with long polling
Configuring dead letter queues (DLQ) for error handling
Integrating AWS messaging with Spring Boot applications
Building event-driven architectures with SQS/SNS

Examples

Quick Setup

Dependencies:

<dependency>
    <groupId>software.amazon.awssdk</groupId>
    <artifactId>sqs</artifactId>
</dependency>
<dependency>
    <groupId>software.amazon.awssdk</groupId>
    <artifactId>sns</artifactId>
</dependency>

Client Configuration:

SqsClient sqsClient = SqsClient.builder()
    .region(Region.US_EAST_1)
    .credentialsProvider(DefaultCredentialsProvider.create())
    .build();

SnsClient snsClient = SnsClient.builder()
    .region(Region.US_EAST_1)
    .build();

SQS Operations

Create and Send Message:

String queueUrl = sqsClient.createQueue(CreateQueueRequest.builder()
    .queueName("my-queue")
    .build()).queueUrl();

String messageId = sqsClient.sendMessage(SendMessageRequest.builder()
    .queueUrl(queueUrl)
    .messageBody("Hello, SQS!")
    .build()).messageId();

Receive and Delete Message:

ReceiveMessageResponse response = sqsClient.receiveMessage(ReceiveMessageRequest.builder()
    .queueUrl(queueUrl)
    .maxNumberOfMessages(10)
    .waitTimeSeconds(20)
    .build());

response.messages().forEach(message -> {
    processMessage(message.body());
    sqsClient.deleteMessage(DeleteMessageRequest.builder()
        .queueUrl(queueUrl)
        .receiptHandle(message.receiptHandle())
        .build());
});

FIFO Queue:

Map<QueueAttributeName, String> attributes = Map.of(
    QueueAttributeName.FIFO_QUEUE, "true",
    QueueAttributeName.CONTENT_BASED_DEDUPLICATION, "true"
);

String fifoQueueUrl = sqsClient.createQueue(CreateQueueRequest.builder()
    .queueName("my-queue.fifo")
    .attributes(attributes)
    .build()).queueUrl();

sqsClient.sendMessage(SendMessageRequest.builder()
    .queueUrl(fifoQueueUrl)
    .messageBody("Order #12345")
    .messageGroupId("orders")
    .messageDeduplicationId(UUID.randomUUID().toString())
    .build());

SNS Operations

Create Topic and Publish:

String topicArn = snsClient.createTopic(CreateTopicRequest.builder()
    .name("my-topic")
    .build()).topicArn();

snsClient.publish(PublishRequest.builder()
    .topicArn(topicArn)
    .subject("Test Notification")
    .message("Hello, SNS!")
    .build());

SNS to SQS Subscription:

String queueArn = sqsClient.getQueueAttributes(GetQueueAttributesRequest.builder()
    .queueUrl(queueUrl)
    .attributeNames(QueueAttributeName.QUEUE_ARN)
    .build()).attributes().get(QueueAttributeName.QUEUE_ARN);

snsClient.subscribe(SubscribeRequest.builder()
    .protocol("sqs")
    .endpoint(queueArn)
    .topicArn(topicArn)
    .build());

Spring Boot Integration

@Service
@RequiredArgsConstructor
public class OrderNotificationService {
    private final SnsClient snsClient;
    private final ObjectMapper objectMapper;

    @Value("${aws.sns.order-topic-arn}")
    private String orderTopicArn;

    public void sendOrderNotification(Order order) throws JsonProcessingException {
        snsClient.publish(PublishRequest.builder()
            .topicArn(orderTopicArn)
            .subject("New Order Received")
            .message(objectMapper.writeValueAsString(order))
            .messageAttributes(Map.of(
                "orderType", MessageAttributeValue.builder()
                    .dataType("String")
                    .stringValue(order.getType())
                    .build()))
            .build());
    }
}

Instructions

Implement Message Processing (with Validation)

Create queues/topics with appropriate configuration
Send messages and validate messageId is returned
Receive messages with long polling (waitTimeSeconds: 20)
Process messages - validate payload before processing
Delete messages only after successful processing - verify deletion response
Check DLQ periodically for failed messages using redrivePolicy
Verify delivery - monitor CloudWatch NumberOfMessagesSent metric

Validation Checklist:

// After send
if (messageId == null || messageId.isEmpty()) {
    throw new MessagingException("Message send failed - no messageId returned");
}

// After receive
if (response.messages().isEmpty()) {
    log.debug("No messages available - normal with long polling");
}

// After delete
if (!deleteResponse.sdkHttpResponse().isSuccessful()) {
    throw new MessagingException("Message deletion failed");
}

Setup Credentials

export AWS_ACCESS_KEY_ID=your-access-key
export AWS_SECRET_ACCESS_KEY=your-secret-key
export AWS_REGION=us-east-1

Monitor and Debug

CloudWatch metrics: ApproximateNumberOfMessages, NumberOfMessagesSent, NumberOfMessagesReceived
Enable SDK logging: software.amazon.awssdk at DEBUG level
Use X-Ray for distributed tracing

Best Practices

SQS:

Use long polling (20-40s) to reduce empty responses and costs
Always delete messages after successful processing
Implement idempotent processing for duplicate handling
Configure DLQ (redrivePolicy) for failed messages
Use FIFO queues when order matters (300 msg/sec limit)

SNS:

Use filter policies to reduce unnecessary deliveries
Keep messages under 256KB
Implement retry with exponential backoff
Monitor NumberOfNotificationFailed metric

General:

Use IAM roles over static credentials
Reuse clients (they are thread-safe)
Test with LocalStack or Testcontainers

Detailed References

Constraints and Warnings

Message Size: Maximum 256KB for SQS and SNS
Visibility Timeout: Undeleted messages reappear after timeout - always delete after processing
Input Validation: Sanitize message body before processing - messages may contain untrusted payloads
FIFO Naming: Must end with .fifo suffix
FIFO Throughput: 300 msg/sec per queue (use partitioning for higher throughput)
Message Retention: SQS retains messages max 14 days
DLQ Required: Configure dead letter queue to prevent message loss
Region-Specific: SQS queues are region-specific; cross-region requires SNS

aws-sdk-java-v2-messaging