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

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

Correct answer is MAJOR

MAJOR version when you make incompatible API changes, MINOR version when you add functionality in a backwards compatible manner, and PATCH version when you make backwards compatible bug fixes.

For details refer to this documentation : https://semver.org/

Allowed methods is an optional configuration. If nothing is specified then all HTTP methods are supported.

Rest all are mandatory.

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.

Mule applications can be scaled vertically by changing worker size. Mule applications can be scaled horizontally by adding more workers.

Paths

The path of an HTTP listener can be static, which requires exact matches, or feature placeholders. Placeholders can be wildcards (*), which match against anything they are compared to, or parameters ({param}), which not only match against anything but also capture those values on a URI parameters map.

Take the following example paths for three listeners using a configuration that establishes api/v1 as the base path:

account/mulesoft/main-contact: only match the exact path request http://awesome-company.com/api/v1/account/mulesoft/main-contact

account/{accountId}/main-contact: matches all path requests structured similarly, such as http://awesome-company.com/api/v1/account/salesforce/main-contact , and save salesforce as the value of accountId.

account/{accountId}/*: matches all path requests different from main-contact, such as http://awesome-company.com/api/v1/account/mulesoft/users , and save mulesoft as the value of accountId.

Mule Ref Doc : https://docs.mulesoft.com/http-connector/1.6/http-listener-ref#paths

To include property. To keep the API definition concise, you can include external content, such as documentation, schemas, and frequently used patterns outside the definition itself. The parser interprets !include as if the content of the externally-hosted file or a URL were declared in-line.

To use the fragments in RAML you have to include the exact path(copy the path) of that fragment you want to use as shown below

Option 3 is the correct as correct syntax is

examples: !include examples/StudentExample.raml

WSDL is used to define the contract in case of SOAP . RAML/OAS is used to REST services

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

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

Graphical user interface Description automatically generated

Only one of the routes in the Choice router executes, meaning that the first expression that evaluates to true triggers that route1 execution and the others are not checked. If none of the expressions are true, then the default route executes. Hence only Route1 will be executed as it is the first expression. hence output of logger is Route1.

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/choice-router-concept

The Choice router dynamically routes messages through a flow according to a set of DataWeave expressions that evaluate message content. Each expression is associated with a different routing option. The effect is to add conditional processing to a flow, similar to an if/then/else code block in most programming languages.

Only one of the routes in the Choice router executes, meaning that the first expression that evaluates to true triggers that route’s execution and the others are not checked. If none of the expressions are true, then the default route executes.

Diagram Description automatically generated

Correct answer is as below. On complete phase only has access to batch job result statistics and payload is not available.

• Total Records Processed: 3
• Successful Records: 3
• Failed Records: 0

On Complete

During this phase, you can optionally configure the runtime to create a report or summary of the records it processed for the particular batch job instance. This phase exists to give system administrators and developers some insight into which records failed to address any issues that might exist with the input data.

Sample output is as below

Mule Ref Doc : https://docs.mulesoft.com/mule-runtime/4.3/batch-processing-concept#on-complete

Correct answer is APP: API RESOURCE NOT FOUND

---------------------------------------------------------------------------------------------------------------------------------------------------

1) A web client submits the request to the HTTP Listener.

2) The HTTP Request throws an "HTTP:NOT_FOUND" error, execution halts.

3) The On Error Propagate error Handler handles the error. In this case ,HTTP:NOT_FOUND error is mapped to custom error APP:API_RESOURCE_NOT_FOUND. This error processor sets payload to APP:API_RESOURCE_NOT_FOUND.

4) “APP:API_RESOURCE_NOT_FOUND. ” is the error message returned to the requestor in the body of the HTTP request with HTTP Status Code: 500

Reference Diagram:

Diagram Description automatically generated with medium confidence

Correct answer is ${training.host}

option 3 is the correct syntz to access application properties

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

Root element is always required while creating XML response in DataWeave transformation

API Exchange creates REST conenctor automtaically once API is published. Hence correct answer is Publish the API specification to Any point Exchange

Correct answer is Creates and manages discoverable assets to be consumed by line of business developers.

C4E does not get directly involved in projects.

POM.xml contains info about the project and configurationn details used by Maven to build the project

Process section is must to get compiles. Process section must have one or more processors

Diagram Description automatically generated

Publish consume: Synchronous. Publish: Asynchronous.

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"

}

}

Bottom of Form

Its primary function is to design and develop fully functional Mule applications in a hosted development environment.

Attributes are replaced with new attributes from the HTTP Request response.

Attributes include everything apart from Payload/body. For ex: Headers, query parameters, URI parameters.

So, when outbound HTTP request is made, new attributes need to pass the outbound HTTP request and old attributes are replaced.

I have created below diagram to make it easy for you to understand:

Diagram Description automatically generated

Web Services Description Language. WSDL is used to describe SOAP based web services

This is a trick question.

You can call only flows from DataWeave using lookup function. Note that lookup function does not support calling subflows.

A subflow needs a parent context to inherit behaviors from such as exception handling, which a flow does not need

Hence correct answer is Not possible in Mule 4

In case of an error , batch job completes in flight steps and stops further processing.

MuleSoft Doc Ref : Handling Errors During Batch Job | MuleSoft Documentation

The default is all processing will stop but we can change it by Max Failed Record field.

General -> Max Failed Records: Mule has three options for handling a record-level error: Finish processing, Continue processing and Continue processing until the batch job accumulates a maximum number of failed records. This behavior can be controlled by Max Failed Records.

The default value is Zero which corresponds to Finish processing.

The value -1, corresponds to Continue processing.

The value +ve integer, corresponds to Continue processing until the batch job accumulates a maximum number of failed records

Points to remember:

* XML must have a root element.

* XML only allows one root element

* To avoid multiple root issues, you must create a root element for the XML output, whenever we transform output

* When mapping array elements (JSON or JAVA) to XML, wrap the map operations in {(..)}

-{ } are defining the object

( ) are transforming each element in the array as a key/value pair

* The transformation to XML would fail if the above mentioned considerations were not taken into account.

* Thus the transformation script declares a root element as trains and wraps the data in “{( )}“.

Whenever you see such type of question, always look out for root element followed by {( )} wrapping map.

I call this a "Wrap The Map" scenario. Hope it would help you remember !

Correct answer is The city is #[payload.City]

Answer can get confused with the option #["The city is" ++ payload.City] But note that this option will not print the space between is and city name. This will print The city isPune

The APIkit Router is a key message processor that validates requests against the provided definition, enriches messages (for example by adding default values to the messages) and routes requests to a particular flow. Also, the Router raises errors messages if errors occurs while routing, validating or processing the user request.

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.

Diagram Description automatically generated

The flow can be described as below. 1) First HTTP POST requets is made in which paylaod is set to 1 and it gets returned to our mail flow. 2) Second call is initiated for JMS Publish Consume JMS: num1 which add 1 to the payload which makes it as 2. Note that pubih consume is a synchronous operation. Hence paylaod is returned to main flow. 3) Third call is initiated for JMS Publish JMS: num2 which add 1 to the payload . Note that pubih is asynchronous operation. Hence paylaod is never returned to main flow. So payload in main flow is still 2. 4) Finally Set Payload increments payload by 1 making payload as 3 which is returned by the flow. Hence option 3 is the correct answer.

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

Correct answer is Array.

Flatten turns a set of subarrays (such as [ [1,2,3], [4,5,[6]], [], [null] ]) into a single, flattened array (such as [ 1, 2, 3, 4, 5, [6], null ]).

This example defines three arrays of numbers, creates another array containing those three arrays, and then uses the flatten function to convert the array of arrays into a single array with all values.

Source

%dw 2.0

output application/json

var array1 = [1,2,3]

var array2 = [4,5,6]

var array3 = [7,8,9]

var arrayOfArrays = [array1, array2, array3]

---

flatten(arrayOfArrays)

Output

[ 1,2,3,4,5,6,7,8,9 ]

Correct answer is Validation modules Is Number operation.

Mule 4 does not use filters anymore. The functionality provided by filters in Mule 3 can be achieved by using the Validation Module.

Pick First is not valid type. Rest all are valid type of event processor.

Choice : https://docs.mulesoft.com/mule-runtime/4.3/choice-router-concept

Round Robin : https://docs.mulesoft.com/mule-runtime/4.3/round-robin

First Successful : https://docs.mulesoft.com/mule-runtime/4.3/first-successful

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

Logs would look like:

INFO 2021-06-09 19:14:56,039 [[MuleRuntime].uber.06: [validationtest].batch-job-validationtestBatch_Job-work-manager @6de10f3e] [processor: validationtestFlow/processors/1/route/0/route/0/aggregator/processors/0; event: bfb751e1-9939-11eb-9f69-02053763653a] org.mule.runtime.core.internal.processor.LoggerMessageProcessor:

[

“\”A\””,

“\”C\””,

“\”D\””

]

—-

INFO 2021-06-09 19:15:02,486 [[MuleRuntime].uber.06: [validationtest].batch-job-validationtestBatch_Job-work-manager @6de10f3e] [processor: validationtestFlow/processors/1/route/0/route/0/aggregator/processors/0; event: bfb751e1-9939-11eb-9f69-02053763653a] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: [

“\”E\””

]

Batch aggregator value is 3. Hence in first time it will print [“A”, “C”, “D”] and in next iteration it will print [ “E” ]

--------------------------------------------------------------------------------------------------------------------------------------------------

Correct answer is [ “E” ]

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

MuleSoft Doc Ref : https://docs.mulesoft.com/api-manager/2.x/policy-mule3-tutorial-manage-an-api#to-add-the-tier

Steps to create SLA Tier are as follows:

1) In API Manager, in API Administration, click a version.

2) Check that the API supports resource-level policies: On the API version details page, in Status, click Configure Endpoint, and check that Type is RAML.

3) Choose the SLA Tiers, and click Add SLA Tier. Set up limit on SLA tier

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

Correct answer is Publish the API to Anypoint Exchange

Anypoint Exchange makes this possible by making it discoverable in below ways

1) In private exchange for internal developers

2) In a public portal for external developers/clients

Here is diagram created by me to help you understand sequence:

Diagram Description automatically generated

Correct answer is Configure the correct JDBC driver as error message suggests the same

• Caused by: java.sql.SQLException: Error trying to load driver: com.mysql.jdbc.Driver : Cannot load class 'com.mysql.jdbc.Driver': [
• Class 'com.mysql.jdbc.Driver' has no package mapping for region 'domain/default/app/mule_app'.,
• Cannot load class 'com.mysql.jdbc.Driver': [

Correct answer is */status as it is the correct way to use wildcards while configuring path value in HTTP listener

As dependency is not present in Mulesoft Maven repository, we need to install the dependency on computer's local Maven repository.

https://docs.mulesoft.com/mule-runtime/4.3/maven-reference

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

Organization Administrators can approve/revoke/delete SLA tier access requests via API Manager only

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