Cognizant Salesforce Developer Trainee Interview Questions and Answers

Life Cycle hooks in LWC are methods that allow you to interact with the component at specific stages of its lifecycle.

• There are four main life cycle hooks in LWC: connectedCallback, disconnectedCallback, renderedCallback, and errorCallback.

• connectedCallback is called when a component is inserted into the DOM.

• disconnectedCallback is called when a component is removed from the DOM.

• renderedCallback is called after the com...read more

There are multiple ways to communicate between components in Salesforce, including using events, public properties, and Apex methods.

• Using events to communicate between components

• Passing data through public properties

• Invoking Apex methods to share data

Yes, future methods can be called from a batch class in Salesforce.

• Future methods can be called from batch classes to perform asynchronous processing.

• This can be useful for offloading long-running tasks to future methods to avoid hitting governor limits.

• Example: Calling a future method from a batch class to update records in Salesforce asynchronously.

The @track decorator in Salesforce is used to track changes to a property in a Lightning web component.

• Used to make a property reactive and trigger re-renders when its value changes

• Not mandatory but recommended for properties that need to be reactive

• Use @track when you want changes to a property to be reflected in the UI

APEX CPU Limit Exceeded error happens when code consumes too much CPU time. Best practices include optimizing code, reducing loops, and using asynchronous processing.

• Avoid using nested loops and optimize code for better performance

• Use asynchronous processing like @future or Queueable to offload CPU intensive tasks

• Limit the use of SOQL queries inside loops to reduce CPU consumption

Mixed DML Exception occurs when DML operations are performed on setup and non-setup objects in a single transaction.

• Occurs when DML operations are performed on both setup and non-setup objects in a single transaction

• Setup objects include User, Profile, PermissionSet, etc.

• Non-setup objects include custom objects, standard objects like Account, Contact, etc.

The code will output 'undefined' because variable 'a' is hoisted within the function.

• Variable 'a' is hoisted to the top of the function scope, so when 'console.log(a)' is called, 'a' is undefined.

• To fix this, move the declaration of 'var a=2;' above the 'console.log(a);' statement.

SOQL query to fetch description field from Account and reason for inability to filter

• SOQL query: SELECT Description FROM Account

• Description field is not filterable because it is a long text field

• Long text fields cannot be filtered in SOQL queries

A trigger is a piece of code that is executed before or after a record is inserted, updated, or deleted in Salesforce.

• Triggers are written in Apex and are used to perform custom actions on records.

• Triggers can be executed before or after a record is inserted, updated, or deleted.

• Triggers can be used to enforce validation rules, update related records, or perform other custom logic.

LWC decorators are used to add metadata to class fields or methods. '@api' is used to expose a public property or method.

• LWC decorators are used to enhance the functionality of Lightning web components.

• '@api' decorator is used to expose a public property or method that can be accessed by parent components.

• Other decorators like '@track', '@wire', '@api get', '@api set' are also commonly used in LWC development.

Types of flow in Salesforce include autolaunched flows, screen flows, and scheduled flows.

• Autolaunched flows are triggered by a process or record change

• Screen flows guide users through a series of screens to collect information

• Scheduled flows are executed at a specific time or on a recurring basis

Best practice for writing triggers in Salesforce

• Ensure trigger logic is bulkified to handle multiple records at once

• Use trigger handler classes to separate logic from trigger itself

• Avoid SOQL queries inside loops to prevent hitting governor limits

• Write unit tests to cover trigger logic and ensure proper functionality

Apex is a programming language used in Salesforce for creating custom business logic and functionality.

• Used to write custom code on the Salesforce platform

• Apex classes are used to define data types and methods

• Triggers are used to perform actions before or after records are inserted, updated, or deleted

LWC (Lightning Web Components) are a modern UI framework for building web components in Salesforce.

• LWC allows developers to build components using modern web standards like JavaScript and HTML.

• LWC can be used to create custom user interfaces in Salesforce Lightning Experience.

• LWC can interact with Salesforce data and metadata using Apex controllers and Lightning Data Service.