SF-PD2 Practice Test 12 — 15 Questions

Question 1

A developer needs to write a unit test for an Apex class that performs a callout to an external REST endpoint. The test must not make a real HTTP request and must simulate a successful response with a specific status code and body. Which approach should the developer use?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Implement HttpCalloutMock and register it with Test.setMock before invoking the callout.. HttpCalloutMock is the platform-provided mechanism for stubbing callouts in tests. Implementing respond() and registering the mock with Test.setMock allows the test to return a controlled HttpResponse with a specified status code and body. Other techniques do not prevent the real callout or produce the desired simulated response.

Answer

Use System.assert with a try-catch block to intercept the callout exception and convert it into a fake response.

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Use Test.startTest and Test.stopTest around the callout to suppress the actual HTTP request.

Answer

Set the endpoint URL to a localhost address so the callout fails and returns a simulated error.

Question 2

A developer is optimizing a Visualforce page that displays a large list of Accounts with related Contacts. The page currently uses a standard controller with an <apex:pageBlockTable> and a controller extension that queries all Contacts for each Account in a loop. Users report that the page loads slowly and sometimes times out. Which technique should the developer implement to improve performance?

Accepted Answer

Use a single SOQL query with a subquery to retrieve all Accounts and their Contacts, then iterate over the results to build a map for the page.. Using a single SOQL query with a subquery to fetch Accounts and their Contacts in one call eliminates the N+1 query problem, where a separate query is made for each Account's Contacts. This reduces database load, avoids governor limits, and significantly improves page load time. The developer should then process the results into a map for efficient access in the Visualforce page.

Answer

Enable lazy loading on the <apex:pageBlockTable> by setting the 'reRender' attribute to load Contacts only when a user expands a row.

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Implement pagination using the StandardSetController to limit the number of Accounts displayed per page, thereby reducing the number of Contacts queried.

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Cache the Contact records in Platform Cache and retrieve them on subsequent page loads to avoid repeated queries.

Question 3

A developer is building a Lightning Web Component that must expose a public method callable from an Aura component on the same page. The method accepts a string and returns a promise that resolves with a boolean. Which TWO steps are required to make this method callable from the Aura parent? (Choose two.)

Accepted Answer

Annotate the method with @api and declare it as a public property or method on the Lightning Web Component class.. Exposing a Lightning Web Component method to an Aura parent requires two things: the method must be decorated with @api so the framework registers it as public, and the Aura parent must obtain the element reference, typically via component.find with an aura:id, to call that method. The promise returned is handled asynchronously by the Aura caller, matching the stated contract.

Answer

Register the method name in the component's .js-meta.xml file under the targetConfigs section.

Answer

Wrap the Lightning Web Component inside an aura:method declaration so the Aura parent can call it directly.

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Add the method to the component's exported functions list using the export keyword alongside the @api decorator.

Question 4

A developer needs to write an Apex test class for a service that makes a callout to an external REST API. The test method must simulate the callout response without making an actual HTTP request. Which approach should the developer use?

Accepted Answer

Implement the `HttpCalloutMock` interface and use `Test.setMock` to register the mock before calling the service method.. The correct approach is to implement the `HttpCalloutMock` interface and register it with `Test.setMock`. This allows the test to simulate the external API response without making a real HTTP request. Other options do not provide a way to mock callouts; they either do not prevent the callout or are unrelated to mocking.

Answer

Annotate the test method with `@isTest(SeeAllData=true)` to allow the callout to access external data.

Answer

Replace the callout with a `@future` method and test the future method using `Test.stopTest` to force execution.

Answer

Use `Test.startTest` and `Test.stopTest` to isolate the callout and prevent it from executing during the test.

Question 5

A developer is creating a Lightning Web Component that will be placed on a Lightning record page for the Case object. The component must display the case's subject and status. Which approach correctly retrieves the record data so the component updates automatically when the record changes?

Accepted Answer

Import getRecord from lightning/uiRecordApi and wire it with the recordId property, then reference fields on the returned record.. The getRecord wire adapter from lightning/uiRecordApi provides a reactive subscription to a single record through Lightning Data Service. Wiring it with the recordId property means the component receives updates whenever the record changes, satisfying the automatic refresh requirement. Apex calls, form components, and notify-change utilities do not provide this reactive single-record retrieval pattern.

Answer

Use the lightning-record-form base component and read its output attributes to populate the display.

Answer

Call an Apex method from connectedCallback that queries the Case by Id and assign the result to a tracked property.

Answer

Import getRecordNotifyChange and call it inside renderedCallback to fetch the latest field values.

Question 6

A developer has a Lightning Web Component that calls an Apex controller method returning 5,000 Account records to render in a custom table. Users report the component takes several seconds to become interactive. The developer wants to reduce the initial payload and rendering time. Which change is the most effective?

Accepted Answer

Implement pagination or infinite loading so Apex returns only the records currently needed, and use @AuraEnabled(cacheable=true) where the data is read-only.. The dominant cost when rendering thousands of rows is the size of the serialized payload plus the number of DOM nodes created. Returning only the current page and marking read-only methods cacheable minimizes both transfer and render work, which is the standard Lightning Web Component performance pattern for large lists.

Answer

Increase the Apex heap size by setting a higher limit in the Apex class and re-deploy.

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Wrap the entire table in lightning-datatable and pass all 5,000 records to it at once.

Answer

Move the Apex call into a @wire property and rely on the framework to automatically chunk the results.

Question 7

A developer is writing an Apex test class for a controller that uses a Visualforce page with a standard controller. The test must cover pagination logic that relies on the StandardSetController. Which TWO actions should the developer take to ensure the test is reliable and covers the pagination behavior? (Choose two.)

Accepted Answer

Use Test.setCurrentPage() to set the Visualforce page context and then instantiate the StandardSetController with a query locator.. To reliably test pagination with StandardSetController, the test must create enough records to span multiple pages and then invoke the pagination methods. Additionally, setting the Visualforce page context with Test.setCurrentPage() and instantiating the StandardSetController with a query locator ensures the controller operates as it would in a real page. These two actions together exercise the pagination logic and verify the expected behavior across pages.

Answer

Set the page size to a large number so that all test records fit on one page, simplifying the test and avoiding pagination complexities.

Answer

Use Test.startTest() and Test.stopTest() to isolate the pagination logic and reset governor limits between pages.

Answer

Use Test.isRunningTest() in the controller to bypass the query and return a hardcoded list of records for pagination testing.

Question 8

A developer needs a Lightning Web Component placed on a record page to read the 18-character id of the record currently being viewed, without querying the database or calling Apex. Which approach provides this value directly?

Accepted Answer

Declare a public property with @api recordId and reference it in the component.. The platform injects the current record id into an @api property named recordId when an LWC is placed on a Lightning record page. This is the direct, no-Apex way to obtain the id. User info adapters, navigation state, and Visualforce page parameters do not supply the record id in this context.

Answer

Query the record id in Apex using ApexPages.currentPage().getParameters().

Answer

Call the getUserInfo wire adapter and read the currentRecordId field from the result.

Answer

Read the value from the page state by calling NavigationMixin.Navigate with a state object.

Question 9

A developer is building a Lightning web component that needs to retrieve a large dataset from a custom object and display it in a paginated table. The component must minimize the number of server round-trips and adhere to Salesforce governor limits. Which approach should the developer use?

Accepted Answer

Use an Apex controller with `@AuraEnabled(cacheable=true)` and implement keyset pagination using `WHERE` clauses on an indexed field.. Keyset pagination using `WHERE` clauses on indexed fields is the recommended approach for large datasets. It avoids the performance degradation of `OFFSET` and minimizes server round-trips by fetching only the needed records. Using `@AuraEnabled(cacheable=true)` allows caching, further reducing server calls. This method adheres to governor limits and provides efficient pagination.

Answer

Use a `@wire` adapter with `getRecord` to fetch all records at once and implement client-side pagination.

Answer

Use the `lightning-datatable` component with the `getRecords` wire adapter to fetch data in chunks.

Answer

Use an Apex controller with `@AuraEnabled(cacheable=true)` and implement pagination using `OFFSET` in SOQL queries.

Question 10

A developer is building an Apex REST service that must accept an inbound JSON payload from an external system. The external system sends an array of order records, and the developer needs the JSON keys (such as order_id) to map directly to Apex property names (such as order_id) without any manual transformation. Which approach should the developer use to deserialize the payload into Apex objects?

Accepted Answer

Use JSON.deserialize with a wrapper class whose properties match the JSON keys exactly.. JSON.deserialize with a wrapper class is the correct choice because Salesforce maps JSON keys to Apex property names that match exactly, including underscores. The other options either require manual mapping, produce untyped collections, or perform the opposite operation. When key names already align with Apex properties, the typed deserialize method is the most direct and maintainable solution.

Answer

Use JSON.createParser and manually read each field into the wrapper class.

Answer

Use JSONGenerator to write the payload into a wrapper instance.

Answer

Use JSON.deserializeUntyped and then cast the resulting Map to an Apex wrapper class.

Question 11

A developer is preparing a deployment of a new Apex class and its test class to production. The test class uses @TestSetup to insert 200 Account records, and each of six test methods queries all 200 Accounts. The deployment fails during validation with a CPU timeout error. Which change most directly addresses the timeout without reducing coverage?

Accepted Answer

Replace the full-object queries with selective SOQL that filters and returns only the fields and rows each test actually needs.. CPU timeouts in test execution usually trace to expensive query volume. Querying every row with every field six times forces the platform to materialize a large result set repeatedly. Tightening the SOQL so each test retrieves only the fields and rows it needs cuts CPU consumption directly while keeping the same behavioral assertions and coverage.

Answer

Move the Account insertion into each test method instead of @TestSetup so each method gets a fresh set of records.

Answer

Annotate the test class with @isTest(OnInstall=false) to defer test execution until after the package is installed.

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Convert the test methods to use System.runAs() so the queries execute under a user with fewer permission checks.

Question 12

A developer is troubleshooting an Apex class that intermittently throws a System.LimitException during integration tests. The developer needs to see the exact sequence of method calls and the values of variables at each step without modifying the class. Which Salesforce feature should the developer use?

Accepted Answer

Apex Replay Debugger. Apex Replay Debugger consumes a captured debug log and replays execution with breakpoints, variable inspection, and call-stack navigation, all without altering the class. Because the failure is intermittent and occurs during integration tests, the developer can capture a log of the failing run and replay it to find the exact point where the limit is exceeded.

Answer

The Apex Test Execution page in Setup

Answer

Checkpoints in the Developer Console

Answer

Debug Log levels set to FINEST for Apex Code

Question 13

A developer is building a Lightning Web Component that must render a large list of order records retrieved from Apex. The component displays each order's formatted total, which follows the user's locale (for example, 1.234,56 € in Germany versus $1,234.56 in the US). Which approach correctly formats each order total for the current user?

Accepted Answer

Import the formatNumber function from lightning/i18n and call it with the numeric value and the appropriate format string.. Formatting numbers for the running user requires respecting the Salesforce locale, not the browser locale. The lightning/i18n module's formatNumber function is the supported way to format numeric values client-side so results match the user's Salesforce locale. Relying on browser-based formatting or Apex-side string concatenation produces inconsistent output across users and locales.

Answer

Use the toLocaleString() method on the JavaScript Number object inside the component's renderedCallback.

Answer

Call the Apex method with a @AuraEnabled(cacheable=true) annotation and rely on Apex to return the formatted string.

Answer

Bind the raw numeric field from Apex directly into the template and let the browser's Intl.NumberFormat format it automatically.

Question 14

A developer has written an Apex class that queries for a large number of records and processes them in a loop. The developer notices that the transaction is hitting the heap size limit. Which technique should be used to process the records in smaller batches to avoid exceeding the limit?

Accepted Answer

Use Database.executeBatch to implement a batch Apex class that processes records in batches.. Batch Apex is specifically designed to handle large data volumes by splitting the work into manageable chunks. Each batch executes in its own transaction, so heap size and other governor limits apply per batch rather than to the entire data set. Implementing Database.Batchable and invoking it with Database.executeBatch allows the developer to process records efficiently without exceeding limits.

Answer

Use a SOQL query with a LIMIT clause and process records in chunks using a recursive trigger.

Answer

Use a for loop with a SOQL query inside to retrieve records one at a time.

Answer

Use the @future annotation to process records asynchronously in a single method.

Question 15

A developer is building a reusable Lightning Web Component that exposes public properties and methods to its parent, and needs to fire an event the parent can handle. Which TWO techniques are valid for this parent-child interaction? (Choose two.)

Accepted Answer

Annotate a property with @api so the parent can set it declaratively in markup or imperatively via the component instance.. Direct parent-child communication in LWC uses two complementary mechanisms: @api exposes properties and methods so a parent can pass data down or invoke a child method, and CustomEvent lets the child notify the parent upward, with the parent listening through the on<eventname> template attribute. Reaching into the parent from the child, using LMS for a direct parent-child relationship, or relying on global window state each violates the framework's encapsulation and reactivity model.

Answer

Use Lightning Message Service to publish a message the parent subscribes to, since LMS is required for any parent-child communication.

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Store shared state on a window-level global variable so both parent and child can read and write it directly.

Answer

Call the parent's method directly by querying the parent component with this.template.querySelector on the root element.