MCD-Level-1 MuleSoft Certified Developer - Level 1 (Mule 4) Questions and Answers

The HTTP 415 Unsupported Media Type client error response code indicates that the server refuses to accept the request because the payload format is in an unsupported format. The format problem might be due to the request's indicated Content-Type or Content-Encoding , or as a result of inspecting the data directly. In this case as per RAML specification data is expected in application/json and in request Content-Type is set as "text/plain" which is incorrect. Hence solution is set the request Content-Type header to application/json

https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/415

Correct answer is Select only Attach Project Sources only

You must keep the Attach Project Sources option selected to be able to import the packaged JAR file back into a Studio workspace.

Deselect the Include project modules and dependencies option.

This option skips bundling the actual modules and external dependencies required to run the Mule application in a Mule runtime engine, creating a lightweight JAR file package that does not include any dependencies specified in the Mule application’s pom.xml file.

The generated JAR file is not a functional deployable archive and cannot be deployed to a Mule runtime engine, but instead offers a way to archive only the source files that make up the Mule application. This is the same as using the -lightWeightPackage flag when packaging using the Mule Maven Plugin and is useful if you want to distribute your project to other Studio installations because it only keeps a reference to all its dependencies. When you import a lightweight package into Studio, all your dependencies are automatically downloaded

MuleSoft Doc Ref : https://docs.mulesoft.com/studio/7.8/import-export-packages

option 3 is the correct syntz to access application properties

For Each Scope

The For Each scope splits a payload into elements and processes them one by one through the components that you place in the scope. It is similar to a for-each/for loop code block in most programming languages and can process any collection, including lists and arrays. The collection can be any supported content type, such as application/json, application/java, or application/xml.

General considerations about the For Each scope:

By default, For Each tries to split the payload. If the payload is a simple Java collection, the For Each scope can split it without any configuration. The payload inside the For Each scope is each of the split elements. Attributes within the original message are ignored because they are related to the entire message.

For Each does not modify the current payload. The output payload is the same as the input.

Mule Doc Reference : https://docs.mulesoft.com/mule-runtime/4.3/for-each-scope-concept

Scatter-Gather sends the event to each routes concurrently. Hence both route in this example will start in parallel. So total time to complete processing is 40 seconds

The Scatter-Gather component is a routing event processor that processes a Mule event through different parallel processing routes that contain different event processors. Each route receives a reference to the Mule event and executes a sequence of one or more event processors. Each of these routes uses a separate thread to execute the event processors, and the resulting Mule event can be either the same Mule event without modifications or a new Mule event with its own payload, attributes, and variables. The Scatter-Gather component then combines the Mule events returned by each processing route into a new Mule event that is passed to the next event processor only after every route completes successfully.

The Scatter-Gather component executes each route in parallel, not sequentially. Parallel execution of routes can greatly increase the efficiency of your Mule application and may provide more information than sequential processing.

Mule Ref Doc : https://docs.mulesoft.com/mule-runtime/4.3/scatter-gather-concept

Correct answer is as below.After all processing routes have finished execution, the Scatter-Gather component creates a new Mule event that combines all resulting Mule events from each route, and then passes the new Mule event to the next component in the flow.

{

"0": {

"attributes": ...,

"payload": "100"

},

"1": {

"attributes": ...,

"payload": "200"

}

}

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In this case both the flows can start without any error and requests can be received on both ports. Flow names httpListener1 can call other flow using HTTP request without any issues.

Hence correct answer is

The mule application start successfully

Web client requests can  be received at URI on port 2222 and on port 3333.

Lets check why other options are incorrect

1) The mule application fails to start. There is URL path conflict because both HTTP Listeners are configured with same path  ---- This is incorrect as port value is different in both listeners

2) The mule application start successfully. Web client requests can only be received at URI on port 2222 but not on port 3333  --- This is incorrect as there is no reason for not receiving requests on port 3333

3) The mule application fails to start because of the port binding conflict as HTTP request also use same port i.e. 3333 --- Port binding conflict will not happen in this case. It would have if both listener configurations would have been on same port . But that is not the case here.

Mule Ref Doc : HTTP Listener Reference - Mule 4 | MuleSoft Documentation

Correct answer is 8 as events are processed in parallel in case of scatter gather router

Correct answer is as below. Attributes in the incoming xml payload are always accessed using @.Similarly *item is required as we have multiple items in the request

%dw 2.0

output application/csv

---

payload.sale.*item map ((value, index) -> {

index: index,

sale: value.@saleId,

itemName: value.desc,

itemPrice: (value.quantity) * (value.price),

item: value.@itemId

} )

Correct answer is Subflow has no error handling implementation where as sync flow has.

Subflow

A subflow processes messages synchronously (relative to the flow that triggered its execution) and always inherits both the processing strategy and exception strategy employed by the triggering flow. While a subflow is running, processing on the triggering flow pauses, then resumes only after the subflow completes its processing and hands the message back to the triggering flow.

Synchronous Flow

A synchronous flow, like a subflow, processes messages synchronously (relative to the flow that triggered its execution). While a synchronous flow is running, processing on the triggering flow pauses, then resumes only after the synchronous flow completes its processing and hands the message back to the triggering flow. However, unlike a subflow, this type of flow does not inherit processing or exception strategies from the triggering flow.

This type of flow processes messages along a single thread, which is ideally suited to transactional processing

URL parameters are always accessed using { } like => {customerID}

vars: Keyword for accessing a variable, for example, through a DataWeave expression in a Mule component, such as the Logger, or from an Input or Output parameter of an operation. If the name of your variable is myVar, you can access it like this: vars.myVar

Hence correct answer is Account Type: #[vars.accountType]

Database always return rows as an array.

Array is the correct answer

The First Successful router iterates through a list of configured processing routes until one of the routes executes successfully. This is sequential execution. In all other options mentioned in the question ,we can achieve parallel execution.

In General > Request > Query Parameters, click the plus icon (+) to add a parameter to a request. Type a name and value for the parameter or use a DataWeave expression to define the name and value.

Graphical user interface, text, application, email Description automatically generated

MuleSoft Documentation Reference : https://docs.mulesoft.com/db-connector/1.9/database-connector-select

Metadata is stored in application-types.xml flle located under src/main/resources.

Mule 4 applications contain an application-types.xml file, which is where metadata around your data types is stored. For example, if you create a new CSV type, that metadata will be added to this file. This new file is easy to share, commit, and merge when conflicts arise, which enables you to do more metadata-driven development.

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/intro-studio#metadata-storage

Variables are stored under Mule event. Please refer to below image for the hierarchy .

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Correct answer is as below as concatenation operation works only with string and not with the objects. In this case payload is object.

"You called the function '++' with these arguments:

1: String ("INFO")

2: Object ({student: {name: "Anay" as String {class: "java.lang.String"},age

Correct answer is Save the payload from the Database SELECT operation to a variable

Response from HTTP request will override the payload and hence response of database SELECT can be lost. Best way to preserve is to assign payload of first operation to variable using TransformMessage.

Correct answer is

%dw 2.0

output application/json

import modules::Utility

---

Utility::encryptString( "John Smith" )

DataWeave 2.0 functions are packaged in modules. Before you begin, note that DataWeave 2.0 is for Mule 4 apps. For Mule 3 apps, refer to DataWeave Operators in the Mule 3.9 documentation. For other Mule versions, you can use the version selector for the Mule Runtime table of contents.

Functions in the Core (dw::Core) module are imported automatically into your DataWeave scripts. To use other modules, you need to import the module or functions you want to use by adding the import directive to the head of your DataWeave script, for example:

import dw::core::Strings

import camelize, capitalize from dw::core::Strings

import * from dw::core::Strings

The way you import a module impacts the way you need to call its functions from a DataWeave script. If the directive does not list specific functions to import or use * from to import all functions from a function module, you need to specify the module when you call the function from your script. For example, this import directive does not identify any functions to import from the String module, so it calls the pluralize function like this: Strings::pluralize("box").

Transform

%dw 2.0

import dw::core::Strings

output application/json

---

{ 'plural': Strings::pluralize("box") }

Correct answer is as below as it follows the correct syntax.

• http:
• basepath: "api"
• host : "localhost"
• port : "8081"

Mule Doc Reference : https://docs.mulesoft.com/mule-runtime/4.3/mule-app-properties-to-configure

As can be seen in error message , SOAP service findFlights expects the SOAP paylaod. This can be set using transform message processor which forms SOAP payload before the Consume operation that contains the destination query parameter

Correct answer is System layer

System APIs provide a means for insulating the data consumers from the complexity or changes to the underlying backend systems.

MuleSoft recommends three-layered approach to API-led connectivity, highlighting the three layers:

* System APIs

* Process APIs

* Experience APIs

System APIs are the core systems of record underlying core systems of record (e.g. ERPs, key customer and billing systems, databases, etc.). Process APIs allow you to define a common process which the organization can share, and these APIs perform specific functions, provide access to non-central data, and may be built by either Central IT or Line of Business IT. And finally, the Experience APIs are the means by which data can be reconfigured so that it is most easily consumed by its intended audience, all from a common data source.

The three-layered structure allows for a seamless flow of data from systems of record to new experiences, and allows for reusability of assets rather than point to point connections. This approach provides a distributed and tailored approach to architecture, greater flexibility through loose coupling, and deeper operational visibility into what is being built.

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Correct syntax to use where clause is WHERE city = :city AND state = :state

This question validates knowledge on using dynamic queries in DB select operation.

Configure Dynamic Queries in the Select Operation

When you need to parameterize not only the WHERE clause but also parts of the query itself (for example, queries that compare tables that depend on a condition, or complex queries for which the project table columns need to vary), you can configure dynamic queries.

In the following example, you configure a dynamic query by using a full expression with a string in which the table depends on a variable $(vars.table). Although some of the query text is dynamic ("SELECT * FROM $(vars.table)), the WHERE clause still defines the WHERE condition using input parameters: in this case, WHERE name = :name.

In your Studio flow, select the Select operation.

In the operation configuration screen, set the SQL Query Text field to SELECT * FROM $(vars.table) WHERE name = :name.

Set the Input Parameters field to {'name' : payload}.

The following screenshot shows the configuration in Studio:

Graphical user interface, application Description automatically generated

Figure 3. Dynamic query configuration

In the XML editor, the  configuration looks like this:

• #["SELECT * FROM $(vars.table) WHERE name = :name"]
• #[{'name' : payload}]

You can apply input parameters only to parameters in a WHERE clause. To modify any other part of the query, use the DataWeave interpolation operator.

Mule Ref Doc: Query a Database Examples - Mule 4 | MuleSoft Documentation

Correct answer is API manager

Creates reusable APIs and assets designed to be consumed by other business units

Correct answer is Nothing needs to be changed in the other APIs or their associated applications

This is the benefit of having separate interface layer. As there are no changes to interface , no changes are required on the API's which consumes this API in context

Correct answer is ${training.host}

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How to Configure Properties to Mule 4.X Platform?

1) Go to /src/main/resources project directory.

2) Create a configuration file with the name configuration.yaml inside the newly created config folder.

                                          Graphical user interface, application, Word Description automatically generated

3) Go To Project > Global Element > Create > General >select the configuration.yaml file create in step- 2)

                                             Graphical user interface, application Description automatically generated 

4) To verify develop a simple flow with HTTP listener which has above entries. Put the logger that prints the values on console.

                                              Graphical user interface, application Description automatically generated

5) Additional info: Similarly, when you want to access this port in DataWeave you need to use p function

                                             Graphical user interface, text, application, email Description automatically generated

PUT replaces the original version of the resource, whereas the PATCH method supplies a set of instructions to modify the resource

To compare, DataWeave syntax is #[payload == "FR"].

In this case only one = is used so it will give syntax error.

Hence the correct answer is A dataweave syntax error

Correct answer is Creates a mock service for an API

API Notebook is an open source, shareable web application for API documentation, interactive API tutorial and example generatation, and a client for your API endpoints. Using API Notebook, you can make requests and quickly transform the responses into readable format. However it cannot be used to mock service for an API.

MuleSoft Doc Ref : https://docs.mulesoft.com/api-manager/1.x/api-notebook-concept

You can choose Attach Project Sources to include metadata that Studio requires to reimport the deployable file as an open Mule project into your workspace. You must keep the Attach Project Sources option selected to be able to import the packaged JAR file back into a Studio workspace. But requirement here is to create smallest deployable archive that will successfully deploy to Cloudhub. Hence we can ignore this option.

We need to select Include project module and dependencies

As actual modules and external dependencies required to run the Mule application in a Mule runtime engine

Hence correct answer is

Select only below option 2) Include project module and dependencies

MuleSoft Doc Ref : https://docs.mulesoft.com/studio/7.5/import-export-packages#exporting-a-studio-project-to-a-deployable-mule-application

Correct answer is async sub flow. Rest are valid flows in Mule.

Sub flow is always synchronous.

Anypoint Exchange provided a way to publish , share and search API's.

MuleSoft Doc Ref : https://docs.mulesoft.com/exchange/

Correct answer is 0.1 vCores

MuleSoft Doc Ref : https://docs.mulesoft.com/runtime-manager/cloudhub-architecture#cloudhub-workers

CloudHub Workers

Workers are dedicated instances of Mule runtime engine that run your integration applications on CloudHub. The memory capacity and processing power of a worker depends on how you configure it at the application level.

Worker sizes have different compute, memory, and storage capacities. You can scale workers vertically by selecting one of the available worker sizes:

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* When a client application is registered in Anypoint Platform, a pair of credentials consisting of a client ID and client secret is generated.

* When the client application requests access to an API, a contract is created between the application and that API.

* An API that is protected with a Client ID Enforcement policy is accessible only to applications that have an approved contract.

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Correct Answer: In the organization's public API portal in Anypoint Exchange, from an approved client application for the API proxy

The List operation returns an array of messages in which: Each message holds the file’s content in its payload. The file’s attributes section carries the file’s metadata (such as name, creation time, and size). The payload is empty if the element is a folder.

Correct answer is Merges elements of two lists (arrays) into a single list

MuleSoft Doc Reference : https://docs.mulesoft.com/mule-runtime/4.3/dw-core-functions-zip

An object store is a facility for storing objects in or across Mule applications. Mule runtime engine (Mule) uses object stores to persist data for eventual retrieval. Internally, Mule uses object stores in various filters, routers, and other message processors that need to store states between messages.

Object stores are available in all deployment targets. If you deploy your application to CloudHub, you can also use Object Store V2.

Correct answer is Key/value pair in Object store

MuleSoft Documentation reference : https://docs.mulesoft.com/mule-runtime/4.3/mule-object-stores#use-cases

Gold is not valid category for connector types.

MuleSoft Doc Ref : https://docs.mulesoft.co m/mule-runtime/3.7/anypoint-connectors#connector-support-categories

Text Description automatically generated with medium confidence

Correct answer is vars."customer"."firstName"

Please note that you can also access firstName using this syntax vars.customer.firstName.

Mule Ref Doc : Variables in Mule Apps | MuleSoft Documentation

lookup(String, Any, Number)

This function enables you to execute a flow within a Mule app and retrieve the resulting payload.

It works in Mule apps that are running on Mule Runtime version 4.1.4 and later.

Similar to the Flow Reference component (recommended), the lookup function enables you to execute another flow within your app and to retrieve the resulting payload. It takes the flow’s name and an input payload as parameters. For example, lookup("anotherFlow", payload) executes a flow named anotherFlow.

Correct answer is

lookup( "createCustomerObject", {first: "Aice, last: "Green"})

MuleSoft Documentation Reference : https://docs.mulesoft.com/mule-runtime/4.3/dw-mule-functions-lookup

Scatter-Gather Router

The Scatter-Gather component is a routing event processor that processes a Mule event through different parallel processing routes that contain different event processors. Each route receives a reference to the Mule event and executes a sequence of one or more event processors. Each of these routes uses a separate thread to execute the event processors, and the resulting Mule event can be either the same Mule event without modifications or a new Mule event with its own payload, attributes, and variables. The Scatter-Gather component then combines the Mule events returned by each processing route into a new Mule event that is passed to the next event processor only after every route completes successfully.

The Scatter-Gather component executes each route in parallel, not sequentially. Parallel execution of routes can greatly increase the efficiency of your Mule application and may provide more information than sequential processing.

Mule Ref Doc : https://docs.mulesoft.com/mule-runtime/4.3/scatter-gather-concept

Option 1 is the only correct choice due to two reasons. 1) Concatenation is always with ++ sign and not with + sign which makes option 2 and 3 wrong 2) hearders can be accessed with attributes. headers and not with only headers which makes option 4 incorrect

Lets revise few concepts RAML which can help us to find the answer of this question.

URI Parameters

Lets have a look at below example.

• /foos:
• /{id}:
• /name/{name}:

Here, the braces { } around property names define URI parameters. They represent placeholders in each URI and do not reference root-level RAML file properties as we saw above in the baseUri declaration. The added lines represent the resources /foos/{id} and /foos/name/{name}.

Query Parameters

Now we'll define a way to query the foos collection using query parameters. Note that query parameters are defined using the same syntax that we used above for data types:

• /foos:
• get:
• description: List all Foos matching query criteria, if provided;
• otherwise list all Foos
• queryParameters:
• name?: string
• ownerName?: string

Based on the above information , below is the only option which defines storeid as uri parameter and department as query parameter.

• /{storeId}:
• get:
• queryParameter:
• department:

Transform Message Add write_date is coverting payload in JSON format and same JSON payload is avaialble to file write processor. However, if the payload is a different format (for example, not CSV) , you can place the transformation inside the Write operation to generate content that will be written without producing a side effect on the message in transit. This is not done in this case. By default, the connector writes whatever is in the message payload. Hence JSON payload will be written to file.

Flow Reference Component

Flow Reference routes the Mule event to another flow or subflow, executes all processors in the referenced flow, and then routes the event back within the same Mule application. The following diagram shows the order of processing when one flow references another:

When the main flow is triggered, the Mule event travels through and executes the flow until the event reaches the Flow Reference. The event then travels through and executes the referenced flow from beginning to end, and then returns to the main flow.

This process enables you to treat the entire referenced flow like a single component in your current flow.

Mule Ref Doc : https://docs.mulesoft.com/mule-runtime/4.3/flowref-about

Correct answer is

• payload
• quantity var
• color query param