Important Salesforce Plat-Dev-301 Exam Questions

Answer: D

Explanation:

When building global applications in Lightning Web Components (LWC), developers should never hardcode locale-specific logic. Salesforce provides a robust Internationalization (i18n) service that exposes the current user's regional settings directly to the JavaScript controller.9

The correct approach is to import the @salesforce/i18n module (Option D). This module contains several properties that are automatically populated based on the logged-in user's Salesforce profile settings. Specifically, the firstDayOfWeek property 10returns an integer (0 for Sunday, 1 for Monday, etc.) that corresponds to the cultural standard of the user's locale.

Using this built-in property is superior to other methods because:

It requires no Apex callouts or SOQL queries (unlike Option A and C).

It is automatically maintained by Salesforce; as global standards change, the platform updates the i18n values, ensuring the component remains compliant without developer intervention.

It avoids the maintenance overhead of creating custom metadata (Option B) to map every possible locale to a starting day.

By leveraging @salesforce/i18n/firstDayOfWeek, the developer ensures the calendar component is truly global and provides a native, localized experience for every user regardless of their country.

Answer: A, D

Explanation:

The provided trigger contains two major violations of Salesforce Apex best practices.

SOQL inside a Loop (Option D): The query for Region__c is located inside the for loop. If 200 accounts are updated at once, the trigger will attempt to run 200 queries, immediately hitting the governor limit of 100 SOQL queries per t35ransaction. To fix this, the developer must 'bulkify' the trigger by collecting all the Region_Name__c values into a Set, performing a single query outside the loop, and storing the results in a Map for quick access.

Redundant DML in a Before Trigger (Option A): This is a before insert and before update trigger. In the 'before' context, changes made to Trigger.new records are automatically committed to the database when the trigger finishes. Adding an explicit update accountList; is not only unnecessary but will cause the trigger to re-fire (recursion), leading to performance issues and potential 'Maximum stack depth' errors.

By removing the redundant DML and moving the query outside the loop, the trigger becomes efficient, scalable, and follows the platform's execution model correctly.

Answer: D

Explanation:

When dealing with large-scale data maintenance, such as deleting a million records daily, Batch Apex is the most robust and scalable solution provided by the Salesforce platform. Batch Apex is specifically designed for processing high volumes of records by breaking the total record set into manageable 'batches' (defaulting to 200 records per batch). This prevents the transaction from hitting platform governor limits, such as the limit on the total number of DML statements or the maximum number of records processed in a single transaction. By scheduling a Batch class, the system handles the heavy lifting asynchronously, ensuring that org performance is not negatively impacted during peak hours.

Other options are unsuitable for this scale. Using @future methods for recursive processing is a poor practice because Salesforce prohibits calling a future method from another future method, and it is difficult to monitor or manage the execution flow. Aggregate functions and AggregateResult o1bjects are used for calculations and data grouping, not for DML operations like deletion. Similarly, SOSL is optimized for text-based searching across multiple objects and returns a limited number of results, making it inappropriate for an exhaustive cleanup of a million records. Batch Apex allows for the use of a QueryLocator, which can handle up to 50 million records, providing the necessary throughput for this high-volume requirement.

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Answer: B

Explanation:

When a Visualforce page is slow because it attempts to load a massive dataset all at once, the bottleneck is often the time taken by the controller constructor to query and process those records before the page can even begin to render. Lazy Loading (Option B) is a strategy where the developer avoids loading all data during the initial page initialization.

Instead of querying 10,000 records in the constructor, the developer can load only the structural elements of the page first. Then, using an action method (triggered by or a window.onload script), the data is fetched in the background. This allows the user to see the page layout immediately while the data 'populates' shortly after. This significantly improves the Time to First Byte (TTFB) and the perceived performance of the page.

Option A (transient) is excellent for reducing the View State size and speeding up postbacks (button clicks), but it does not inherently speed up the initial load time of a large dataset. Option C (JavaScript processing) can help but doesn't solve the data retrieval bottleneck. Option D (actionPoller) is used for periodic updates and is not an efficient way to load an initial large dataset. Lazy loading ensures that the 'heavy lifting' is decoupled from the initial page load, providing a more responsive experience.

Answer: A

Explanation:

Visualforce provides two primary ways to perform AJAX-style operations: JavaScript Remoting and Remote Objects. The primary benefit of JavaScript Remoting (Option A) is its ability to execute complex server-side logic.

JavaScript Remoting works by calling an Apex method annotated with @RemoteAction. Because this is a standard Apex method, it can perform advanced calculations, complex SOQL queries with multi-object joins, DML operations across various objects, and even call out to external web services.

In contrast, Remote Objects are purely declarative. They allow you to perform basic CRUD operations (Create, Read, Update, Delete) on a single object directly from JavaScript without writing any Apex. While Remote Objects are easier to set up for simple data entry, they cannot handle 'business logic' (like calculating a discount based on customer history) during the data retrieval process.

Option B and C describe Remote Objects, not Remoting. Option D is a feature of standard Visualforce tags like , but not a specific differentiator for Remoting. Therefore, when your application needs 'brains' on the server, JavaScript Remoting is the superior choice.