SF-PD2 Practice Test 13 — 15 Questions

Question 1

A developer needs a Lightning Web Component to expose a public method so that an Aura component on the same page can call it and pass a string parameter. Which approach should the developer use?

Accepted Answer

Define a public method in the LWC and annotate it with @api.. Lightning Web Components expose public methods to parent Aura components by decorating them with @api. The Aura component can then call the method on the LWC element reference. Other options either do not provide a callable instance method, use asynchronous messaging that lacks return values, or confuse data provisioning with method exposure, so they do not meet the requirement.

Answer

Use Lightning Message Service to publish a message that the Aura component subscribes to.

Answer

Declare the method inside a wire adapter in the LWC.

Answer

Define the method as a static method on the LWC class.

Question 2

A developer needs to write a SOQL query that retrieves all Account records with their related Opportunities, but only Opportunities that are in the 'Closed Won' stage. Which SOQL query correctly achieves this?

Accepted Answer

SELECT Id, Name, (SELECT Id, Name FROM Opportunities WHERE StageName = 'Closed Won') FROM Account. The correct query uses a subquery in the SELECT clause to retrieve related Opportunities with a filter on StageName. This returns all Accounts and includes only Closed Won Opportunities for each. Filtering child records must be done within the subquery. The other options either incorrectly filter in the outer query, fail to filter the child records, or reference a non-existent field on Account.

Answer

SELECT Id, Name, (SELECT Id, Name FROM Opportunities WHERE StageName = 'Closed Won') FROM Account WHERE StageName = 'Closed Won'

Answer

SELECT Id, Name, (SELECT Id, Name FROM Opportunities WHERE StageName = 'Closed Won') FROM Account WHERE Id IN (SELECT AccountId FROM Opportunity WHERE StageName = 'Closed Won')

Answer

SELECT Id, Name, (SELECT Id, Name FROM Opportunities) FROM Account WHERE Opportunities.StageName = 'Closed Won'

Question 3

A developer needs to expose an Apex method so that a Lightning web component can call it and receive a list of Account records. The method must be static and the component uses the wire service to invoke it. Which annotation combination should the developer apply to the Apex method?

Accepted Answer

@AuraEnabled(cacheable=true) on a static method that returns a List.. The wire service requires a static Apex method annotated with @AuraEnabled(cacheable=true) and a serializable return type such as List. Cacheable enables the wire adapter to cache results and refresh on reactive parameter changes. Instance methods and non-cacheable annotations do not satisfy the wire service contract.

Answer

@AuraEnabled(cacheable=true) on a static method that returns a custom inner class instance.

Answer

@AuraEnabled on a static method with no cacheable attribute, returning a List<Account>.

Answer

@AuraEnabled(cacheable=true) on an instance method that returns a List<Account>.

Question 4

A developer is building an Apex batch class that processes 2 million Account records. The start method returns a QueryLocator for all Accounts, but the batch job fails during execution with a 'First error: Apex CPU time limit exceeded' message. The execute method performs several SOQL queries inside a loop over the batch scope records. Which approach should the developer use to resolve the CPU time limit issue while keeping the batch design intact?

Accepted Answer

Move the SOQL queries out of the loop by collecting record IDs first, then performing a single bulk query before iterating over the scope records.. Querying inside a loop is the classic cause of CPU and SOQL limit failures in batch Apex. Bulkifying by collecting IDs, running one query with a WHERE Id IN :ids filter, and building a Map for lookup eliminates repeated work per record. This keeps each batch transaction comfortably inside CPU and query limits while preserving the existing batch structure and scope size.

Answer

Set the Database.executeBatch scope parameter to 1 so each transaction handles a single record.

Answer

Increase the batch size from 200 to 2000 so fewer batches are processed overall.

Answer

Change the start method to return an Iterable instead of a QueryLocator so records can be streamed lazily.

Question 5

A developer needs to give a CI service account the ability to run the Apex test suite in a production org without interactive login, and the pipeline must not store a user's personal password. Which authentication approach should the developer configure?

Accepted Answer

Authenticate the CI job with a connected app using the JWT bearer flow and authorize the integration user in advance.. The JWT bearer flow with a connected app and a pre-authorized integration user provides headless, passwordless authentication for CI, since the pipeline signs a JWT with a certificate instead of storing user credentials. This satisfies the requirement to run Apex tests in production without interactive login or a personal password.

Answer

Store the integration user's username and password in an encrypted pipeline variable and authenticate with sf org login web.

Answer

Use the SOAP login call with the integration user's credentials and a security token appended to the password.

Answer

Generate a personal access token in the org's setup and pass it to the CLI with the sf org login access-token command.

Question 6

A developer is building a Lightning Web Component that needs to display a list of 200 accounts with their annual revenue, and the component's Apex controller currently executes a SOQL query inside a loop over the accounts to fetch related opportunities. Users report slow load times. What is the most effective way to improve performance?

Accepted Answer

Use a single SOQL query with a subquery to retrieve accounts and their related opportunities in one call, then process the results in memory.. The performance bottleneck is the N+1 query pattern: one query for accounts, then a separate query for each account's opportunities. Consolidating into a single query with a subquery eliminates the repeated database calls, reduces governor limit usage, and speeds up the component. Processing in memory is efficient because the data volume is manageable.

Answer

Increase the query batch size by using Database.getQueryLocator with a higher scope size.

Answer

Move the SOQL query into a future method to run asynchronously, and then poll for results.

Answer

Add a @AuraEnabled(cacheable=true) annotation to the Apex method to enable client-side caching.

Question 7

A developer is designing an Apex class that must support dependency injection so that unit tests can substitute a fake implementation of a service interface. The production code should use the real service, while tests inject a stub. Which two techniques should the developer use to achieve this? (Choose two.)

Accepted Answer

Use a static variable of the interface type that tests can override before invoking the class.. Dependency injection in Apex is typically achieved either by passing an interface implementation through the constructor or by exposing a static variable of the interface type that tests can reassign. Both approaches let production code use the real service while tests supply a stub, without embedding test-only conditionals in the production class. The interface is the key abstraction that makes substitution possible.

Answer

Use Test.isRunningTest inside the production class to return a hardcoded stub instead of the real service.

Answer

Declare the service implementation as a private inner class so tests can instantiate it directly.

Answer

Annotate the class with @isTest to allow it to be replaced during test execution.

Question 8

A developer is optimizing a Visualforce page that displays a large table of Opportunity records. The page uses a StandardSetController and iterates over the records to display fields. Users report that the page loads slowly, and the developer notices that the page makes a SOQL query for each Opportunity to retrieve the Owner's Name. The developer wants to improve performance by reducing the number of queries. What is the most efficient way to achieve this?

Accepted Answer

Use a SOQL query with a relationship query to retrieve the Owner's Name along with the Opportunity records in the StandardSetController.. The performance issue is caused by the page making a separate SOQL query for each Opportunity to get the Owner's Name. By using a relationship query in the StandardSetController, the Owner's Name is retrieved in the same query as the Opportunities. This reduces the total number of queries to one, significantly improving page load time. The other options either do not reduce queries or add unnecessary complexity.

Answer

Create a formula field on Opportunity that references the Owner's Name and display that field in the Visualforce page.

Answer

Enable lazy loading on the Visualforce page so that Owner's Name is loaded only when the user scrolls to that row.

Answer

Use a Platform Cache to store the Owner's Name for each Opportunity and retrieve it from the cache instead of querying.

Question 9

A developer is preparing to deploy a complex change set from a sandbox to production. The change set includes Apex classes, Visualforce pages, and a new custom object. The developer runs all tests in the sandbox and achieves 100% coverage, but the deployment to production fails with the error: 'Your organization's code coverage is 68%. You need at least 75% coverage to complete this deployment.' What is the most likely cause of this discrepancy?

Accepted Answer

The production org has existing Apex classes that are not covered by the tests in the change set, lowering the overall coverage.. The deployment failed because Salesforce requires 75% overall code coverage across the entire organization, not just the new code. Production likely contains legacy Apex classes that are not covered by the tests in the change set. To resolve this, the developer must include tests that cover those existing classes or ensure that the deployed tests exercise them.

Answer

The production org has a higher number of asynchronous Apex jobs that interfere with test execution.

Answer

The sandbox and production have different API versions, causing the tests to run differently.

Answer

The change set does not include the test classes, so they are not run in production.

Question 10

A developer is troubleshooting a Lightning Web Component that calls an Apex method returning many records and notices the component re-fetches the same data every time the user navigates back to the tab. The developer wants to avoid redundant server calls for read-only data. Which change should be made?

Accepted Answer

Annotate the Apex method with @AuraEnabled(cacheable=true) and call it through a @wire adapter or wired property.. Client-side caching for read-only Apex is provided by marking the method cacheable and consuming it through @wire, which routes through Lightning Data Service. That lets the framework reuse previously fetched data instead of issuing a new server call each time the component loads, directly eliminating the redundant fetches described.

Answer

Store the Apex results in a static variable in the controller so subsequent calls return the cached list.

Answer

Move the Apex logic into a Flow and invoke the Flow from the component on each render.

Answer

Add @AuraEnabled(cacheable=false) and call the method imperatively on every connectedCallback.

Question 11

A developer is building a Lightning Web Component that includes a lightning-button. The button's click handler is defined as an arrow function in the component's JavaScript file. The developer wants to pass the event object to the handler to access the event's target. Which syntax should be used in the component's HTML template to correctly bind the handler and pass the event?

Accepted Answer

. The correct syntax is to use onclick={handleClick} without parentheses or the event object. Lightning Web Components automatically pass the event object to the handler when the event occurs. The handler can then access event.target and other properties. The other options incorrectly attempt to invoke the function during template rendering or use unsupported syntax.

Answer

<lightning-button onclick={handleClick.bind(this)} label="Click"></lightning-button>

Answer

<lightning-button onclick={handleClick()} label="Click"></lightning-button>

Answer

<lightning-button onclick={handleClick(event)} label="Click"></lightning-button>

Question 12

An integration test in a sandbox must verify that a callout to an external pricing service returns a parsed response. The test class currently attempts the real callout and fails with a 'Methods defined as TestMethod do not support Web service callouts' error. Which change should the developer make?

Accepted Answer

Implement HttpCalloutMock and register it with Test.setMock() before the code under test invokes the callout.. Apex tests are isolated from external systems, so any callout must be replaced with a mock. Implementing HttpCalloutMock and registering it via Test.setMock() lets the code under test receive a controlled response, allowing the developer to assert on parsing, status handling, and error branches without a live service.

Answer

Wrap the callout in Test.startTest() and Test.stopTest() so the platform permits external requests.

Answer

Add the @future(callout=true) annotation to the method performing the callout.

Answer

Grant the running user the 'Make Callouts in Tests' permission in the test class profile.

Question 13

A developer is building a Lightning Web Component that must surface a toast notification when an Apex callout returns a specific error code. The component is used inside a Salesforce mobile app and on desktop. Which module should the developer import to display the toast?

Accepted Answer

import { ShowToastEvent } from 'lightning/platformShowToastEvent';. Toasts in Lightning Web Components are shown by dispatching a ShowToastEvent, which must be imported from the lightning/platformShowToastEvent module. This approach is the documented, cross-platform method supported in Lightning Experience and the Salesforce mobile app. The other modules either do not exist, serve unrelated purposes such as record data access or notifications, or would cause compilation errors.

Answer

import { ToastEvent } from 'lightning/notifications';

Answer

import Toast from 'lightning/toast';

Answer

import { showToast } from 'lightning/uiRecordApi';

Question 14

A developer needs to write a test method for an Apex class that performs a callout to an external web service. The test must not make an actual callout and should simulate a successful response. Which approach should be used?

Accepted Answer

Use Test.setMock with an implementation of HttpCalloutMock. Test.setMock with an HttpCalloutMock implementation is the standard way to simulate callouts in Apex tests. It allows you to define the response that the callout should return, so the test can verify the logic that processes the response. This approach ensures that no actual callout is made and that the test is deterministic and fast.

Answer

Use Test.isRunningTest() to conditionally skip the callout

Answer

Use HttpRequest with a mock endpoint URL

Answer

Use Database.executeBatch with a mock callout handler

Question 15

A developer is creating a Lightning Web Component that must expose a public property so that a parent Aura component can pass a record ID into it. The LWC is embedded inside the Aura component using aura:component with an attribute. Which decorator and configuration should the developer use on the LWC property?

Accepted Answer

Decorate the property with @api and define it as a public property in the LWC's .js file.. To allow an Aura parent to pass data into an LWC child, the LWC property must be part of its public API. The @api decorator makes a property public and settable from the parent's markup or JavaScript. When the Aura component uses an attribute with the same name, the framework maps it to the public property. Without @api, the property remains private and the parent cannot set it.

Answer

Decorate the property with @track and define a getter and setter in the LWC's .js file.

Answer

Decorate the property with @wire and import the record ID using lightning/uiRecordApi.

Answer

Define the property without any decorator and rely on the Aura component to set it via aura:attribute.