Salesforce Certified MuleSoft Developer I Exam Dumps & Practice Test Questions

Question 1:

Given that the Mule application has no global error handlers and the Validation component in the private flow raises an error, what response will the main flow’s HTTP Listener return to the web client?

A. "Parent error"
B. "Child error"
C. "Parent completed"
D. "Validation Error"

Correct Answer: B

Explanation:

In MuleSoft applications, error handling follows a propagation model where errors in a sub-flow or private flow bubble up to the parent flow if no specific error handlers are defined. In this scenario, the Mule application lacks any global error handler configuration, meaning there is no mechanism to intercept and handle errors globally.

The error occurs in the Validation component inside the private flow, which acts as a child flow invoked by the main flow (parent flow). When the Validation component throws an error, it is initially classified as a “child error” because its origin is the sub-flow context.

Because no global or local error handlers are present to catch and process this error, the error travels up to the parent flow, essentially notifying the parent that something failed downstream. However, the parent flow does not handle the error either, and so it cannot complete its processing successfully.

The response returned by the HTTP Listener connected to the main flow reflects the source of the error. Since the error started in the child (private) flow and no custom message is configured, the default behavior is to indicate a “child error.” This terminology is part of Mule’s error handling semantics that differentiate errors by their origin in the flow hierarchy.

The other options are incorrect for the following reasons:

• A (“Parent error”) is wrong because the error originates in the child flow, not the parent.

• C (“Parent completed”) is incorrect because the parent flow does not complete successfully due to the unhandled error.

• D (“Validation Error”) might sound related but is not the standard label unless explicitly configured; Mule categorizes it as a “child error” since it stems from the private flow.

Thus, the correct response message returned to the client is “Child error”, making Option B the right answer.

Question 2:

How should you correctly define a DataWeave function named toUpper that accepts a string parameter userName and returns it in uppercase?

A. var toUpper(userName) = upper(userName)
B. fun toUpper(userName) = upper(userName)
C. var toUpper(userName) -> upper(userName)
D. fun toUpper(userName) -> upper(userName)

Correct Answer: B

Explanation:

In DataWeave, defining functions follows a specific syntax using the fun keyword. Functions encapsulate reusable logic and can accept parameters. The general syntax is:

Here, fun declares the function, followed by the function name and parameters in parentheses, an equal sign (=), and finally the expression that returns the value.

The question requires defining a function toUpper that takes a string userName and returns it converted to uppercase using the built-in upper function.

Now, let’s examine each option:

• Option A: Uses var to define toUpper as var toUpper(userName) = upper(userName). In DataWeave, var declares variables, not functions, so this syntax is invalid for function definition.

• Option B: Uses fun toUpper(userName) = upper(userName). This is the correct and standard syntax for defining a function in DataWeave. The fun keyword properly declares the function, and the function body uses the upper function to convert the input string.

• Option C: Uses var with a -> symbol (var toUpper(userName) -> upper(userName)), which is invalid syntax in DataWeave. The arrow (->) is not used for function declaration, and var cannot declare functions.

• Option D: Uses fun correctly but pairs it with -> (fun toUpper(userName) -> upper(userName)), which is incorrect. DataWeave requires = to assign the function’s expression, not ->.

Therefore, Option B correctly follows DataWeave’s function declaration syntax by using fun and = to define the function body, making it the right choice.

Question 3:

A Mule application polls data from a database table, but when running, it logs an error related to accessing the database. 

Which configuration in the Database connector needs to be corrected to fix this issue?

A. Use the correct JDBC driver.
B. Use the correct host URL for the database server.
C. Use the correct database name.
D. Use the correct table name.

Correct Answer: D

Explanation:

When a Mule application connects to a database and polls data from a table, it depends heavily on the correct configuration of several parameters in the Database connector. The error logged suggests that the application is having trouble locating or querying the database table specified in its configuration.

Firstly, let’s analyze the possible causes:

• Option A (JDBC driver) is crucial for establishing the connection. However, if the connection is successful and the error occurs during querying, it is unlikely that the JDBC driver is the issue. A wrong JDBC driver usually causes connection failures, not table-specific errors.

• Option B (host URL) identifies where the database server resides. Connection issues here would prevent any communication with the database, leading to connection errors rather than table query errors. Since the error happens during polling, the connection itself is probably fine.

• Option C (database name) specifies which database to access on the server. If this was incorrect, the connection would fail or the database would be unreachable. Again, a connection failure would manifest differently, so this is unlikely.

• Option D (table name) is the specific object within the database that the Mule application tries to query. If the table name is misspelled, missing, or does not exist, the database cannot fulfill the query, causing an error. This matches the error scenario exactly.

Therefore, the root cause of the error is almost certainly due to an incorrect table name configuration in the Database connector. This could be caused by simple typos, case sensitivity, or referencing a table that doesn't exist in the connected database. Ensuring the table name matches exactly as it appears in the database resolves the issue.

Correcting the table name in the Database connector configuration enables the Mule application to successfully poll the database, eliminating the error and restoring functionality.

Question 4:

A web client sends a POST request containing XML data to the ACME Orders API but receives an error response. 

What should be modified in the request headers to ensure a successful response from the API?

A. Add a request header: Content-Type = application/octet-stream
B. Add a response header: Content-Type = application/octet-stream
C. Add a response header: Content-Type = application/xml
D. Add a request header: Content-Type = application/xml

Correct Answer: D

Explanation:

When a client sends data to an API via a POST request, it is critical that the server understands the format of the incoming data. This is communicated using the Content-Type header in the HTTP request, which specifies the media type of the request body.

In this case, the client is sending XML data. For the server to properly parse and process this data, the request must explicitly state that the content type is application/xml.

Here is why the other options are incorrect:

• Option A: Setting the Content-Type to application/octet-stream implies that the data is raw binary. This is a generic type and does not inform the server that the data is XML, so the server may fail to parse it correctly, resulting in errors.

• Option B: Modifying the response header does not affect how the server interprets the request payload. The issue here lies in how the server reads the incoming data, so changing response headers is irrelevant.

• Option C: Like option B, this changes the server’s response header, which does not fix problems with the client’s request.

• Option D: Setting the Content-Type header in the request to application/xml correctly informs the server that the payload is XML. This allows the server to parse the XML properly and respond successfully.

In summary, the key to resolving this error is ensuring the API receives a correctly labeled request. Without the correct Content-Type, the server may reject or misinterpret the data. Setting Content-Type: application/xml on the request header is the precise fix, making Option D the right choice.

Question 5:

Which syntax correctly specifies a customer ID as a URI parameter in the path attribute of an HTTP Listener?

A. {customerID}
B. #[customerID]
C. $(customerID)
D. (customerID)

Correct Answer: A

Explanation:

When configuring an HTTP Listener in integration platforms such as MuleSoft, it is essential to correctly define URI parameters to enable dynamic path values. URI parameters serve as placeholders within the URL path that get substituted with actual values during runtime, facilitating dynamic routing and data retrieval.

Option A uses curly braces {customerID}, which is the standard and widely accepted syntax for defining URI path parameters. Platforms like MuleSoft interpret this format as a variable placeholder. For example, if the Listener path is /customers/{customerID}, a request to /customers/123 dynamically passes 123 as the value for customerID. This method is straightforward, intuitive, and well-supported across many API gateway and integration frameworks.

Option B uses the #[customerID] syntax, which resembles the DataWeave expression language in MuleSoft. This notation is meant for embedding dynamic expressions within message payloads or transformations, not for defining URI parameters in the HTTP Listener’s path. It refers to evaluating variables or expressions rather than defining URL path variables.

Option C shows $(customerID), which is commonly found in shell scripting or some templating languages but is not the recognized syntax for HTTP Listener URI parameters. Using this format in the path attribute would likely cause errors or be ignored, as it doesn’t conform to the expected conventions in integration tools like MuleSoft.

Option D uses parentheses (customerID), which is not a valid format for URI parameters in HTTP Listener configurations. Parentheses are typically used for grouping expressions or function calls but not for parameter placeholders in URLs.

To summarize, Option A is the correct syntax because curly braces {} are the standard way to specify dynamic path parameters in an HTTP Listener’s path. This allows the integration platform to extract the actual value from the incoming URL and make it accessible during request processing.

Question 6:

Which DataWeave expression correctly retrieves the value "Max" from a Mule variable named customer?

A. "customer.first"
B. vars."customer"."first"
C. vars."customer.first"
D. customer.first

Correct Answer: B

Explanation:

In MuleSoft’s DataWeave language, accessing variables and their properties requires precise syntax, especially when dealing with complex objects. Here, the variable customer is assumed to be an object with properties first and last, for example: { first: "Max", last: "Mule" }. The goal is to extract the value "Max" which corresponds to the first property.

Option B — vars."customer"."first" — correctly references the variable stored in the vars context, which is the standard location for local variables within a Mule event. Here’s why this works:

• vars refers to the container of all variables.

• "customer" accesses the variable named customer. The quotes around "customer" ensure the key is treated literally, which is useful if keys have special characters or spaces.

• "first" accesses the property first inside the customer object.

This expression will evaluate to "Max" as desired.

Option A is simply a string literal "customer.first" and does not reference the variable or its properties at all. In DataWeave, strings in quotes are treated as text, not variable references, so this would not retrieve the value from the object.

Option C — vars."customer.first" — tries to access a variable with the literal name "customer.first", treating it as a single key rather than nested properties. Since no such variable exists, it would not return the expected value.

Option D — customer.first — could work in certain contexts if customer was in the global scope or directly accessible, but in MuleSoft best practices, variables should be accessed through the vars scope to avoid ambiguity. Without vars, DataWeave might not resolve the variable properly, especially inside message processors.

Thus, the most accurate and reliable expression is B, because it explicitly accesses the variable within the correct context and navigates its nested property properly, returning the value "Max".

Question 7:

If a Mule application lacks any global error handlers and the File Write operation fails with a FILE:CONNECTIVITY error, what message will the web client receive in response?

A. "File written"
B. "ORDER:NOT_CREATED"
C. "FILE:CONNECTIVITY"
D. "OTHER ERROR"

Answer: C

Explanation:

In this situation, the Mule application processes a request to write a file but encounters a connectivity-related error (FILE:CONNECTIVITY) during the File Write operation. Because the application has no global error handlers defined, it will use Mule’s default error propagation mechanism. When an error occurs without custom handling, Mule typically returns the raw error details back to the caller—in this case, the web client.

Option A ("File written") suggests a successful operation, which is inaccurate because the file writing failed due to connectivity issues. Returning a success message would be misleading.

Option B ("ORDER:NOT_CREATED") appears to relate to some business logic or order processing failure, not a file operation error. Since the error is specifically tied to file connectivity, this option is unrelated.

Option D ("OTHER ERROR") is a generic catch-all error message. While it might be used for unknown or uncaught exceptions, it doesn't accurately reflect the specific error type here, which Mule explicitly identifies as FILE:CONNECTIVITY.

Therefore, the correct response is C ("FILE:CONNECTIVITY"), as Mule directly reports this error back to the client in the absence of any custom error handling logic. This behavior is important for diagnosing issues, as it informs the client exactly what went wrong during the processing of their request, helping in troubleshooting and corrective actions.

Question 8:

When observing the Mule event at the Logger component in the main flow, which parts of this event remain unchanged compared to the Mule event that was input to the HTTP Request operation after it completes?

A. The entire Mule event
B. All variables
C. The payload and all attributes
D. The payload and all variables

Answer: D

Explanation:

Understanding the lifecycle of a Mule event as it passes through components such as HTTP Request and Logger is crucial for this question. The Mule event consists of three main parts: the payload, variables, and attributes.

When the main flow invokes an HTTP Request operation to call a child flow’s HTTP Listener, the Mule event may undergo changes depending on how the flows are designed. The payload is the core data being processed, and variables store additional data within the flow context. Attributes typically contain metadata such as headers or properties related to the event.

The HTTP Request operation itself usually does not modify the payload or variables unless the flow explicitly applies transformations or modifications. It sends the request and waits for the response, which might update the payload, but the existing variables in the main flow remain unchanged.

After the HTTP Request completes, the Logger component logs the current state of the Mule event. At this point, the payload and variables are the same as the ones that were input to the HTTP Request operation unless an explicit transformation was done during or after the request. Attributes, however, can change because they often include dynamic information such as HTTP headers or transport properties that differ after an HTTP call.

Option A (the entire Mule event) is incorrect because attributes can change after the HTTP Request. Option B (all variables) excludes the payload, which usually remains unchanged unless specifically altered. Option C (payload and attributes) ignores variables, which persist through the flow.

Thus, D ("The payload and all variables") is correct since these elements stay consistent between the HTTP Request operation and the Logger in the main flow, reflecting how Mule handles event data during HTTP interactions.

Question 9:

What is the primary function of the MuleSoft DataWeave language in an integration project?

A. To define HTTP endpoints for Mule applications
B. To configure Mule application deployment settings
C. To perform data transformation and mapping between different formats
D. To schedule batch jobs and trigger flows

Correct Answer: C

Explanation:

DataWeave is the powerful expression language and transformation engine in MuleSoft that is designed specifically for data transformation and mapping. The primary role of DataWeave is to convert data from one format to another (such as JSON to XML, CSV to JSON, or Java objects to XML) within Mule applications, which is a common requirement in integration projects.

DataWeave enables developers to write concise, readable scripts that transform incoming data into the desired structure needed by downstream systems or applications. This might include reshaping the data structure, filtering elements, or merging fields from multiple sources. It supports a wide range of data formats, making it highly versatile.

Option C correctly identifies DataWeave’s primary function: data transformation and mapping. This capability is essential because integration often involves connecting heterogeneous systems with differing data formats.

Option A is incorrect because HTTP endpoint definition is managed by Mule connectors and configuration, not DataWeave.

Option B is wrong since deployment settings are handled through Anypoint Platform tools and Mule runtime configurations, unrelated to DataWeave.

Option D misrepresents DataWeave’s role; scheduling and batch processing are done using other Mule components such as schedulers and batch jobs, not DataWeave.

Understanding how to leverage DataWeave efficiently is critical to passing the MuleSoft Developer I exam, as it is a core technology for achieving effective integrations and handling complex data scenarios.

Question 10:

In MuleSoft, what is the purpose of a Connector in a Mule flow?

A. To transform data between formats
B. To provide pre-built functionality to connect to external systems
C. To store variables within a flow
D. To manage deployment configurations

Correct Answer: B

Explanation:

Connectors are key components in MuleSoft that provide pre-built, reusable functionality to integrate with external systems, protocols, or services. These can be databases, SaaS applications (like Salesforce, SAP, or Twitter), messaging systems, or HTTP endpoints.

The purpose of a connector is to abstract the complexities of the underlying protocol or API and provide a simple, standardized interface for Mule flows to interact with external resources. This allows developers to focus on business logic instead of handling low-level details such as connection management, authentication, and protocol-specific nuances.

Option B is the correct choice because connectors act as ready-made building blocks to connect Mule applications with external systems efficiently.

Option A is incorrect because data transformation is primarily handled by the DataWeave language or transformers, not connectors.

Option C is wrong as variable storage is managed by flow variables or session variables, which exist within the Mule event context.

Option D is incorrect since deployment configurations are managed outside flows via Anypoint Platform or server settings, not within connectors.

For the Salesforce Certified MuleSoft Developer I exam, knowing the role of connectors and their benefits is essential. Connectors simplify integration by handling the intricacies of communication with external systems, which is a foundational concept tested on the exam.