This DVA-C02 practice question tests your understanding of development with aws services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer runs the command above. The output.txt file is empty. What could be the reason?
The payload is not valid JSON.
Why wrong: Invalid payload may cause error but Lambda would still return an error message.
The Lambda function did not return any output.
Lambda returns the handler's response; if no return, output is empty.
The Lambda function timed out.
Why wrong: Timeout would result in a 503 or error, not empty output.
The function name is incorrect.
Why wrong: Incorrect name would result in ResourceNotFoundException.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The Lambda function did not return any output.
The command likely invokes a Lambda function and writes its response to output.txt. If the file is empty, the most direct reason is that the Lambda function executed successfully but returned no output (i.e., the handler returned `None` or an empty response). The AWS CLI `lambda invoke` command writes the function's response payload to the output file; if the function returns nothing, the file will be empty.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The payload is not valid JSON.
Why it's wrong here
Invalid payload may cause error but Lambda would still return an error message.
The Lambda function did not return any output.
Why this is correct
Lambda returns the handler's response; if no return, output is empty.
Related concept
Read the scenario before looking for a memorised answer.
The Lambda function timed out.
Why it's wrong here
Timeout would result in a 503 or error, not empty output.
The function name is incorrect.
Why it's wrong here
Incorrect name would result in ResourceNotFoundException.
Common exam traps
The trap here is that candidates often assume an empty output file means a failure (like timeout or invalid input), but the question tests the understanding that a Lambda function can complete successfully with no return value, which is a valid execution outcome.
Trap categories for this question
Command / output trap
Timeout would result in a 503 or error, not empty output.
Detailed technical explanation
When using `aws lambda invoke --function-name myFunction --payload '{}' output.txt`, the CLI sends a synchronous `Invoke` API call. The Lambda service returns the response payload in the HTTP body, which the CLI writes to the file. If the handler returns `None` (Python), `null` (Node.js), or an empty string, the response payload is empty, resulting in a zero-byte file. Note that the CLI also writes the `LogResult` (if `--log-type Tail` is used) to stderr, not the output file, so the file only contains the function's return value.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
Quick reference
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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FAQ
Development with AWS Services — This question tests Development with AWS Services — Read the scenario before looking for a memorised answer..
The correct answer is: The Lambda function did not return any output. — The command likely invokes a Lambda function and writes its response to output.txt. If the file is empty, the most direct reason is that the Lambda function executed successfully but returned no output (i.e., the handler returned `None` or an empty response). The AWS CLI `lambda invoke` command writes the function's response payload to the output file; if the function returns nothing, the file will be empty.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This DVA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DVA-C02 exam.
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