Amazon DVA-C02 AWS Certified Developer - Associate Exam Practice Test

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Question 1

A company has an application that uses an AWS Lambda function to process customer orders. The company notices that the application processes some orders more than once.

A developer needs to update the application to prevent duplicate processing.

Which solution will meet this requirement with the LEAST implementation effort?

AImplement a de-duplication mechanism that uses Amazon DynamoDB as the control database. Configure the Lambda function to check for the existence of a unique identifier before processing each event.

BCreate a custom Amazon ECS task to perform idempotency checks. Use AWS Step Functions to integrate the ECS task with the Lambda function.

CConfigure the Lambda function to retry failed invocations. Implement a retry mechanism that has a fixed delay between attempts to handle duplicate events.

DUse Amazon Athena to query processed events to identify duplicate records. Add processing logic to the Lambda function to handle the duplication scenarios that the query identifies.

Answer : A

Requirement Summary:

Orders are being processed more than once

Need to prevent duplicate processing

Looking for least implementation effort

Key Concept:

Lambda + Event-driven patterns can occasionally result in duplicate invocations (at-least-once delivery model)

You need idempotency (i.e., prevent repeated processing of same event)

Evaluate Options:

A . Use DynamoDB for de-duplication

Simple and widely used approach

Store a unique orderId as the primary key

Before processing, check if order exists

If yes skip

If no process and store the ID

Minimal code changes required

B . ECS + Step Functions

Overkill for basic de-duplication

Adds significant complexity

C . Retry logic with fixed delay

Doesn't prevent duplication --- makes it worse

Retrying might trigger the same message again

D . Athena to identify duplicates

Reactive solution, not preventative

Not suitable for real-time event de-duplication

Lambda idempotency: https://docs.aws.amazon.com/lambda/latest/dg/invocation-retries.html

Using DynamoDB for idempotent design: https://aws.amazon.com/blogs/compute/how-to-design-idempotent-APIs-on-aws/

Question 2

A developer built an application that calls an external API to obtain data, processes the data, and saves the result to Amazon S3. The developer built a container image with all of the necessary dependencies to run the application as a container.

The application runs locally and requires minimal CPU and RAM resources. The developer has created an Amazon ECS cluster. The developer needs to run the application hourly in Amazon ECS.

Which solution will meet these requirements with the LEAST amount of infrastructure management overhead?

AAdd a capacity provider to manage instances.

BAdd an Amazon EC2 instance that runs the application.

CDefine a task definition with an AWS Fargate launch type.

DCreate an Amazon ECS cluster and add the managed node groups feature to run the application.

Answer : C

Requirement Summary:

Containerized app

Runs hourly

Minimal CPU and RAM

Goal: Least infrastructure management

Evaluate Options:

A . Add a capacity provider to manage instances

Capacity providers are used for managing EC2-backed ECS clusters, which still require underlying EC2 management.

B . Add an Amazon EC2 instance

Involves managing infrastructure (provisioning, patching, scaling, etc.)

C . Use AWS Fargate launch type

Serverless container runtime

No server management

Easily scheduled using EventBridge + ECS Fargate Task

Best fit for periodic workloads like this

D . Use managed node groups

Applies to EKS (Kubernetes), not ECS

Unnecessary overhead for this use case

Fargate: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/what-is-fargate.html

Scheduled ECS tasks: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/scheduled_tasks.html

Question 3

A company stores its data in data tables in a series of Amazon S3 buckets. The company received an alert that customer credit card information might have been exposed in a data table on one of the company's public applications. A developer needs to identify all potential exposures within the application environment.

Which solution will meet these requirements?

AUse Amazon Athena to run a job on the S3 buckets that contain the affected data. Filter the findings by using the SensitiveData:S30bject/Personal finding type.

BUse Amazon Made to run a job on the S3 buckets that contain the affected data. Filter the findings by using the SensitiveData:S30bject/Financial finding type.

CUse Amazon Made to run a job on the S3 buckets that contain the affected data. Filter the findings by using the SensitiveData:S30bject/Personal finding type.

DUse Amazon Athena to run a job on the S3 buckets that contain the affected data. Filter the findings by using the SensitiveData:S30bject/Financial finding type.

Answer : B

Requirement Summary:

Customer credit card data may be exposed

Data is stored in Amazon S3

Developer must identify all exposure risks

Tool to Use:

Amazon Macie is designed to:

Automatically scan S3 for sensitive data

Detect financial information, PII, credentials, etc.

Finding Type Mapping:

Credit card data maps to: SensitiveData:S3Object/Financial

Evaluate Options:

A . Athena + filtering

Athena is a query engine; it doesn't detect sensitive data automatically

B . Macie + Financial finding type

Correct

Designed for this use case

C . Macie + Personal finding type

Personal maps to names, addresses, etc., not credit cards

D . Athena + Financial

Again, Athena can't classify data -- it only queries structured data

Macie Overview: https://docs.aws.amazon.com/macie/latest/userguide/what-is-macie.html

Finding Types: https://docs.aws.amazon.com/macie/latest/user/findings-types.html

Financial finding type: SensitiveData:S3Object/Financial

Question 4

A real-time messaging application uses Amazon API Gateway WebSocket APIs with backend HTTP service. A developer needs to build a feature in the application to identify a client that keeps connecting to and disconnecting from the WebSocket connection. The developer also needs the ability to remove the client

Which combination of changes should the developer make to the application to meet these requirements? (Select TWO.)

ASwitch to HTTP APIs in the backend service.

BSwitch to REST APIs in the backend service.

CUse the callback URL to disconnect the client from the backend service.

DAdd code to track the client status in Amazon ElastiCache in the backend service.

EImplement $connect and $disconnect routes in the backend service.

Answer : D, E

Requirement Summary:

WebSocket-based messaging app using API Gateway WebSocket APIs

Need to:

Identify clients repeatedly connecting/disconnecting

Be able to remove problematic clients

Evaluate Options:

A . Switch to HTTP APIs

HTTP APIs don't support WebSocket connections

B . Switch to REST APIs

REST APIs are not compatible with WebSockets

C . Use the callback URL to disconnect clients

Possible, but not a direct option

Callback URLs are used for sending messages to connected clients, not for disconnecting

D . Track client status in ElastiCache

Good solution: Store and update connection state (connected, disconnected, timestamps)

Helps track abuse or reconnections

E. Implement $connect and $disconnect routes

Required to capture connection lifecycle events

These can be used to log/store client behavior and decide on removal

WebSocket routes in API Gateway: https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-websocket-api-route-selection.html

Managing WebSocket connections: https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-websocket-api-mapping-template-reference.html

Question 5

A developer uses AWS IAM Identity Center to interact with the AWS CLI and AWS SDKs on a local workstation. API calls to AWS services were working when the SSO access was first configured. However, the developer is now receiving Access Denied errors. The developer has not changed any configuration files or scripts that were previously working on the workstation.

What is the MOST likely cause of the developer's access issue?

AThe access permissions to the developer's AWS CLI binary file have changed.

BThe permission set that is assumed by IAM Identity Center does not have the necessary permissions to complete the API call.

CThe credentials from the IAM Identity Center federated role have expired.

DThe developer is attempting to make API calls to the incorrect AWS account.

Answer : C

Requirement Summary:

Developer uses AWS IAM Identity Center (SSO) with AWS CLI / SDKs

Initially working fine

Now receiving AccessDenied errors

No changes to config or scripts

Key Understanding:

IAM Identity Center credentials are temporary and time-limited. When you use SSO-based access via the AWS CLI (aws sso login), it obtains temporary credentials stored in the local cache.

By default, these expire in 1 hour (can be extended).

Evaluate Options:

A . Permissions to CLI binary changed

Unlikely -- this would produce execution errors, not AccessDenied from AWS API

B . Permission set lacks required permissions

Then the error would have occurred from the beginning, not after time

C . IAM Identity Center credentials expired

Most likely -- user hasn't refreshed credentials using aws sso login again

After expiration, API calls fail with AccessDenied

D . Developer is calling the wrong AWS account

Would likely show different types of errors (AccountNotFound, etc.)

SSO and AWS CLI: https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-sso.html

Troubleshooting SSO CLI: https://docs.aws.amazon.com/cli/latest/userguide/sso-configure-profile-token.html

Question 6

A company needs to develop a proof of concept for a web service application. The application will show the weather forecast for one of the company's office locations. The application will provide a REST endpoint that clients can call. Where possible, the application should use caching features provided by AWS to limit the number of requests to the backend service. The application backend will receive a small amount of traffic only during testing.

Which approach should the developer take to provide the REST endpoint MOST cost-effectively?

ACreate a container image. Deploy the container image by using Amazon EKS. Expose the functionality by using Amazon API Gateway.

BCreate an AWS Lambda function by using AWS SAM. Expose the Lambda functionality by using Amazon API Gateway.

CCreate a container image. Deploy the container image by using Amazon ECS. Expose the functionality by using Amazon API Gateway.

DCreate a microservices application. Deploy the application to AWS Elastic Beanstalk. Expose the AWS Lambda functionality by using an Application Load Balancer.

Answer : B

Requirement Summary:

Simple REST endpoint for weather data

Light backend usage (POC, testing)

Wants caching support to reduce backend calls

Must be cost-effective

Evaluate Options:

B: Lambda + API Gateway + SAM

Serverless = No idle costs

API Gateway can enable caching (response caching at endpoint level)

SAM makes deployment simple and repeatable

Perfect for low-traffic testing

A: EKS + API Gateway

High overhead

Not cost-effective for POC/testing

C: ECS + API Gateway

Similar to A: Container orchestration not needed for light REST endpoint

D: Elastic Beanstalk + ALB + Lambda

Overly complex and does not directly expose Lambda

Beanstalk better suited for full apps, not small REST functions

AWS SAM: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/what-is-sam.html

API Gateway caching: https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-caching.html

Serverless Best Practices: https://docs.aws.amazon.com/lambda/latest/dg/best-practices.html

Question 7

A company operates a media streaming platform that delivers on-demand video content to users from around the world. User requests flow through an Amazon CloudFront distribution, an Amazon API Gateway REST API, AWS Lambda functions, and Amazon DynamoDB tables.

Some users have reported intermittent buffering issues and delays when users try to start a video stream. The company needs to investigate the issues to discover the underlying cause.

Which solution will meet this requirement?

AEnable AWS X-Ray tracing for the REST API, Lambda functions, and DynamoDB tables. Analyze the service map to identify any performance bottlenecks or errors.

BEnable logging in API Gateway. Ensure that each Lambda function is configured to send logs to Amazon CloudWatch. Use CloudWatch Logs Insights to query the log data.

CUse AWS Config to review details of any recent configuration changes to AWS resources in the application that could result in increased latency for users.

DUse AWS CloudTrail to track AWS resources in all AWS Regions. Stream CloudTrail data to an Amazon CloudWatch Logs log group. Enable CloudTrail Insights. Set up Amazon SN5 notifications if unusual API activity is detected.

Answer : A

Requirement Summary:

Users experience buffering/delay when starting video stream

Architecture:

CloudFront API Gateway Lambda DynamoDB

Need to identify root cause of performance issues

Evaluate Options:

A: Enable AWS X-Ray tracing

Ideal for end-to-end tracing

Visualizes latency across services (API Gateway, Lambda, DynamoDB)

Creates a service map for easy identification of bottlenecks or errors

Designed specifically for distributed tracing and performance monitoring

B: CloudWatch Logs Insights

Helpful for querying logs

But lacks the visual trace linkage across services like X-Ray

Does not identify where latency accumulates

C: AWS Config

Tracks configuration changes, not runtime performance

D: CloudTrail + CloudWatch Logs

More useful for audit/logging, not tracing performance or latency issues

X-Ray overview: https://docs.aws.amazon.com/xray/latest/devguide/aws-xray.html

Service map: https://docs.aws.amazon.com/xray/latest/devguide/xray-console-service-map.html

Tracing API Gateway: https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-xray.html