The wire service, combined with @track for private reactive properties or @api for public ones, is the core LWC reactive engine. It ensures the component reacts and re-renders only when the underlying data changes, providing optimal performance. connectedCallback is for initialization logic, renderedCallback runs after every render (and can hurt performance if misused), and complex logic in getters/templates is not the primary reactivity mechanism.

Batch Apex is designed specifically for processing large numbers of records asynchronously while respecting governor limits by working in discrete batches. This is a scalable, platform-supported solution. Catching the exception only informs of failure but doesn’t prevent it. Adding LIMIT clauses can break business logic by not processing all necessary records. Relying on user behavior is unreliable and not a technical solution.

Option A is correct for a BEFORE update trigger. In before triggers, you modify the records in Trigger.new directly (as shown), and the platform commits these changes automatically—no DML is needed or allowed. Option B incorrectly performs a DML update, which is unnecessary and will cause an error. Option C is not bulkified (only looks at the first record). Option D incorrectly modifies Trigger.old, which is read-only.

The decision hinges on the class’s behavior regarding data access. If the class queries or manipulates records in a way that should respect the user’s permissions and sharing rules, it must use ‘with sharing’. Even if it doesn’t query directly, if it calls other methods or passes IDs that lead to data access, the context matters. It is not about the caller’s type or performance, and the developer’s profile is irrelevant to runtime security.

“Named Principal with JWT Token Exchange” is the correct configuration for the OAuth 2.0 JWT Bearer flow. This allows a Salesforce-connected app (the named credential) to authenticate as a service (named principal) rather than on behalf of a specific user, using a signed JWT to obtain an access token. ‘Per User’ requires user context, ‘Password Authentication’ stores credentials, and ‘Anonymous’ provides no authentication.

While the goal is to test trigger logic, not validation rules, a robust test should handle or expect known external constraints. Using try/catch and asserting the expected exception (and its message) validates that the system behaves correctly when the validation rule is violated. SeeAllData=true makes tests fragile and is discouraged. runAs with bypass permission is not a standard practice for this and requires specific setup. loadData doesn’t solve the validation rule issue during insertion.

To test asynchronous Apex (like @future, Queueable, or Schedulable) within the confines of a test method, you must wrap the code that enqueues the job between Test.startTest() and Test.stopTest(). This forces the asynchronous process to run synchronously for the test, allowing you to assert the results. @future methods are not disabled. @isTest(Callout=true) is for making mock callouts, not for executing async code. Callouts can be tested via mocking.

The correct pattern is to use @api for the public, reactive property (accountId). Then, use the @wire decorator to call an Apex method (which must be cacheable=true) that takes the accountId as a parameter. When the parent component changes the @api property, the wire service automatically re-invokes the Apex method with the new value, updating the data reactively. Option A is imperative, not declarative. Option B’s getRecord is for a single record, not a list. Option D’s wire to a getter is for reactive properties, not for calling Apex.

The main issue is maintainability. A monolithic trigger handling all events mixes different business logics, making it difficult to understand, modify, and test in isolation. Best practice is to have a single, minimal trigger per object that delegates to handler classes based on the event type. This promotes separation of concerns. Governor limits are not directly tied to trigger length. There is no line limit for deployment, and compilation impact is negligible compared to the maintenance burden.

The wire service, combined with @track for private reactive properties or @api for public ones, is the core LWC reactive engine. It ensures the component reacts and re-renders only when the underlying data changes, providing optimal performance. connectedCallback is for initialization logic, renderedCallback runs after every render (and can hurt performance if misused), and complex logic in getters/templates is not the primary reactivity mechanism.0