DVA-C02 Practice Test

The AWS Certified Developer – Associate (DVA-C02) is a associate-level AWS certification. The exam has 65 questions, runs 130 minutes, costs $150, and requires a passing score of 720/1000. CertSharp provides 500 exam-style DVA-C02 practice questions — 30 free with no credit card — each with a detailed explanation.

1. Question 2AWS SDKMedium

   An application using an AWS SDK occasionally receives ProvisionedThroughputExceededException from DynamoDB. What is the recommended client-side handling?

   • A

     Retry the request with exponential backoff and jitter to spread out the retries.

   • B

     Retry the request immediately in a tight loop until the call finally succeeds.

   • C

     Switch the SDK to synchronous mode so requests are throttled in strict order.

   • D

     Disable SDK retries so the application fails fast on the very first error seen.

   Show answer & explanation

   Correct answer: A — Retry the request with exponential backoff and jitter to spread out the retries.

   Exponential backoff with jitter spaces out retries and reduces contention during throttling, which most AWS SDKs apply by default. Immediate tight retries amplify load. Synchronous mode does not address throttling, and disabling retries removes resilience to transient errors.

2. Question 3IdempotencyMedium

   A payment Lambda function is sometimes invoked more than once for the same SQS message after a transient error. How can the developer prevent duplicate charges?

   • A

     Switch the function to provisioned concurrency so retries are suppressed at scale.

   • B

     Increase the SQS visibility timeout so the message is processed a single time.

   • C

     Move the queue to a FIFO type, which removes the need for application checks.

   • D

     Store a unique business ID as an idempotency key in DynamoDB to skip duplicates.

   Show answer & explanation

   Correct answer: D — Store a unique business ID as an idempotency key in DynamoDB to skip duplicates.

   Storing a processed idempotency key such as the order ID in DynamoDB with a conditional write lets the function detect and skip duplicates. Provisioned concurrency affects warm capacity, not retries. A longer visibility timeout reduces but does not eliminate duplicates, and FIFO reduces duplicates without guaranteeing exactly-once application behavior.

3. Question 4Amazon DynamoDBMedium

   A developer needs to retrieve all items for a specific customer ID from a DynamoDB table with high efficiency. Which operation should be used?

   • A

     A Query on the partition key equal to the customer ID to read matching items directly.

   • B

     A Scan with a filter expression on the customer ID across the entire table.

   • C

     A BatchGetItem call that returns items grouped by their customer ID value.

   • D

     A GetItem call passing the customer ID as the sort key condition value.

   Show answer & explanation

   Correct answer: A — A Query on the partition key equal to the customer ID to read matching items directly.

   Query reads items by partition key and is efficient because it targets a single partition. Scan reads the whole table and then filters, consuming far more capacity. BatchGetItem needs exact primary keys for each item, and GetItem returns a single item by full primary key, not a customer's set.

4. Question 5AWS LambdaEasy

   A developer wants an AWS Lambda function to process objects as soon as they are uploaded to an Amazon S3 bucket. Which approach invokes the function automatically?

   • A

     Schedule the Lambda function with Amazon EventBridge to poll the bucket each minute.

   • B

     Enable S3 Transfer Acceleration so the bucket pushes objects to the function on write.

   • C

     Configure an S3 event notification that triggers the Lambda function on object-created events.

   • D

     Mount the S3 bucket to the function with Amazon EFS so writes trigger the handler.

   Show answer & explanation

   Correct answer: C — Configure an S3 event notification that triggers the Lambda function on object-created events.

   S3 event notifications invoke Lambda directly on s3:ObjectCreated events, giving near real-time processing with no polling. EventBridge scheduling polls on a timer and adds latency. Transfer Acceleration only speeds uploads and does not invoke functions, and EFS provides shared storage, not event delivery.

5. Question 6Amazon S3Easy

   A developer needs to move infrequently accessed log files to cheaper storage automatically after 30 days while keeping them retrievable. Which S3 feature does this?

   • A

     An S3 event notification that copies objects to a cheaper bucket after 30 days.

   • B

     An S3 Lifecycle rule that transitions objects to a lower-cost class after 30 days.

   • C

     S3 Transfer Acceleration, which reduces the storage cost of aging objects fast.

   • D

     S3 Cross-Region Replication, which moves old objects to a colder Region tier.

   Show answer & explanation

   Correct answer: B — An S3 Lifecycle rule that transitions objects to a lower-cost class after 30 days.

   Lifecycle rules transition objects to classes such as S3 Standard-IA or Glacier on a schedule. Event notifications trigger processing but do not manage tiering. Transfer Acceleration speeds transfers and does not change cost class, and replication copies objects across Regions without changing tiers automatically.

6. Question 7Amazon SNSEasy

   A developer needs one published message to be delivered to several Amazon SQS queues for parallel processing. Which pattern achieves this fan-out?

   • A

     Send the message to one SQS queue configured to copy itself to the others.

   • B

     Publish to an SNS topic that has each SQS queue subscribed to it.

   • C

     Use an EventBridge schedule to push the message to each queue each minute.

   • D

     Write the message to S3 and let each queue read it on object creation event.

   Show answer & explanation

   Correct answer: B — Publish to an SNS topic that has each SQS queue subscribed to it.

   SNS fan-out publishes a message to a topic that delivers a copy to every subscribed SQS queue, enabling parallel consumers. SQS queues cannot replicate themselves. EventBridge scheduling is timer-based, not message-driven, and S3 polling is an indirect workaround, not the intended pattern.

7. Question 8Amazon API GatewayMedium

   A developer wants API Gateway to reject requests with an invalid JSON body before they reach the backend Lambda function. Which feature should be used?

   • A

     A usage plan with an API key that blocks malformed requests at the edge layer.

   • B

     Request validation with a model that enforces the required JSON schema at the API.

   • C

     A Lambda authorizer that inspects each request body for schema violations first.

   • D

     A gateway response mapping that converts invalid bodies into empty payloads now.

   Show answer & explanation

   Correct answer: B — Request validation with a model that enforces the required JSON schema at the API.

   API Gateway request validation checks required parameters and body against a JSON Schema model and returns 400 before invoking the backend. Usage plans throttle and meter by API key, not validate payloads. A Lambda authorizer handles authorization context, and gateway responses customize error output rather than validate input.

8. Question 9Architectural patternsMedium

   A developer is decoupling a monolith so an order service can emit an event and several independent services react without the order service knowing about them. Which pattern is this?

   • A

     Choreography using events, where services react independently to published events.

   • B

     Orchestration, where a central controller invokes each service in fixed sequence.

   • C

     Synchronous request-response, where the order service calls each downstream service.

   • D

     Tight coupling, where services share one database table to coordinate their work.

   Show answer & explanation

   Correct answer: A — Choreography using events, where services react independently to published events.

   Event choreography lets services react to events independently, reducing coupling between producers and consumers. Orchestration centralizes control in a coordinator. Synchronous calls couple the caller to each callee, and sharing a database table tightly couples services through schema.

9. Question 10Amazon EventBridgeMedium

   A developer wants to run a Lambda function whenever an EC2 instance changes to the stopped state. Which EventBridge construct routes this event?

   • A

     An EventBridge schedule that polls EC2 each minute for newly stopped instances.

   • B

     An EventBridge rule with an event pattern matching EC2 instance state-change events.

   • C

     A CloudWatch metric alarm that publishes the instance state to the target function.

   • D

     An SQS queue subscribed to EC2 so it forwards state changes to the target function.

   Show answer & explanation

   Correct answer: B — An EventBridge rule with an event pattern matching EC2 instance state-change events.

   EventBridge rules match AWS service events with an event pattern and route them to targets such as Lambda in near real time. A schedule fires on a timer, not on state changes. CloudWatch alarms act on metric thresholds, and SQS does not subscribe directly to EC2 state events.