Top 25+ Apex Interview Questions and Answers

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Apex is a programming language used in Salesforce to build custom business logic and automate tasks on the platform. It is similar to Java and works directly with Salesforce data. If you are aiming for a Salesforce developer role, knowing Apex is a must. But just knowing how it works is not enough – you also need to answer interview questions clearly and confidently. In this blog, you will find 25+ commonly asked Apex interview questions and answers to help you prepare for your next Salesforce interview.

Fun Fact – Apex is the most commonly used language for Salesforce backend development.

Basic Level Apex Interview Questions

Here are basic-level Apex interview questions in Salesforce to help you build a strong foundation before moving to advanced topics.

1. What is Apex in Salesforce, and how is it different from Java?

Apex is a strongly typed, object-oriented language used to write custom code on the Salesforce platform. It is similar to Java in syntax but designed specifically for working with Salesforce data. Unlike Java, Apex runs in Salesforce’s multitenant environment, so it comes with strict governor limits.

2. What are governor limits in Apex?

Governor limits control how much data or how many resources a single Apex transaction can use. For example, there is a limit of 100 SOQL queries per transaction. These limits help prevent one user’s code from affecting overall system performance.

3. How does a trigger differ from a class in Apex?

A trigger is used to perform actions before or after records are inserted, updated, or deleted. A class is a reusable block of code that contains methods and logic. Triggers respond to data changes. Classes are used to organize and execute reusable code.

4. What is a SOQL query? Can you give an example?

SOQL (Salesforce Object Query Language) is used to fetch records.

Example – 

SELECT Name, Email FROM Contact WHERE LastName = ‘Smith’
It’s similar to SQL but only works with Salesforce objects.

5. What are different data types supported in Apex?

Apex supports primitive types like Integer, String, Boolean, and Date. It also supports complex types like List, Set, Map, and user-defined objects.

6. What is a DML statement? List a few examples.

DML (Data Manipulation Language) statements are used to modify records. Examples include:
insert, update, delete, undelete, and upsert. These statements let you work with Salesforce data in Apex.

Intermediate Level Apex Interview Questions

These intermediate Apex interview questions in Salesforce will test your practical knowledge and how well you can apply Apex in real scenarios.

7. What is the use of static variables in Apex?

Static variables keep their value across multiple method calls during a single execution context. They are often used in triggers to prevent repeated execution in the same transaction. Since they’re class-level, they don’t belong to any one object instance.

8. How do you handle exceptions in Apex?

Apex uses try-catch blocks to handle exceptions. You can catch specific exceptions like DmlException or general ones like Exception. Always add proper logging or meaningful error messages inside the catch block.

9. What are trigger context variables, and how are they used?

Trigger context variables help identify the trigger event and the records involved. For example, Trigger.isInsert checks if the event is an insert. Trigger.new holds the new versions of records. They guide the logic inside the trigger.

10. What is the difference between before and after triggers?

Before triggers run before records are saved to the database. They’re used for validation or setting values. After triggers run after records are saved and are better for updates that rely on record IDs or related objects.

11. Can you call a future method from another future method? Why or why not?

No, you can’t call a future method from another future method. Salesforce blocks it to avoid stacking async calls that can slow down system performance or lead to governor issues.

12. What’s the difference between SOQL and SOSL?

SOQL fetches records from one object based on filters. SOSL searches text across multiple objects. Use SOQL for precise queries and SOSL for full-text searches.

Advanced Level Apex Interview Questions

These advanced Apex interview questions in Salesforce are designed to challenge your expertise and prepare you for complex coding scenarios.

13. How do you avoid trigger recursion in Apex?

To avoid recursion, I use a static Boolean flag or a static Set to track processed records. This way, the logic runs only once per record in a single transaction.

14. How would you bulkify a trigger handling multiple records?

I avoid writing logic inside for loops that call DML or SOQL. Instead, I collect all needed data in one query and perform bulk DML outside the loop. This keeps the trigger efficient and within governor limits.

15. What are the best practices for writing test classes in Apex?

Test classes should cover at least 75% of the code. I write both positive and negative test cases, use @testSetup to prepare data, and isolate tests with SeeAllData = false. Asserts are important to verify logic.

16. How do you handle mixed DML operations in Apex?

Mixed DML occurs when you perform DML on setup and non-setup objects in the same context. To fix this, I use System.runAs() or move the conflicting DML into a @future or Queueable method.

17. How would you optimise a long-running Apex transaction?

I split the logic using Batch or Queueable Apex. I reduce SOQL and DML calls, avoid nested loops, and use selective queries with proper filters. Sometimes, moving logic to asynchronous processing helps reduce runtime drastically.

Apex Scenario Based Interview Questions

This section covers scenario-based Apex interview questions in Salesforce that test your practical skills and problem-solving approach.

18. A user updates a contact’s email – how would you notify the account owner only if the domain changes?

In a before update trigger, I compare the old and new email domains using string split. If the domain has changed, I collect the related account owners and send notifications using Messaging.sendEmail().

19. A trigger is inserting duplicate records – how would you identify and fix the issue?

First, I check if the trigger is running multiple times or lacks proper filtering. Then, I query existing records with matching fields and use a Set to compare. I update the trigger logic to skip records already in the database.

20. How would you update related child records when a parent field is modified?

In an after update trigger on the parent object, I check which field changed. I collect the IDs and query related child records. Then I loop through them, make the updates, and use a single DML statement to save.

Apex Code Interview Questions

Let’s go through some Apex programming interview questions that test your understanding of programming concepts and coding practices in Salesforce.

21. Write an Apex class that returns the total number of contacts for a given Account Id.

public class ContactHelper {

    public static Integer countContacts(Id accountId) {

        return [SELECT COUNT() FROM Contact WHERE AccountId = :accountId];

    }

}

22. Write a method to check if a given string is a palindrome.

public class StringUtils {

    public static Boolean isPalindrome(String input) {

        if (String.isBlank(input)) {

            return false;

        }

        String cleaned = input.replaceAll(‘[^a-zA-Z0-9]’, ”).toLowerCase();

        String reversed = cleaned.reverse();

        return cleaned == reversed;

    }

}

23. Write a method to remove duplicate strings from a list.

public class DeduplicationUtil {

    public static List<String> removeDuplicates(List<String> inputList) {

        Set<String> uniqueItems = new Set<String>(inputList);

        return new List<String>(uniqueItems);

    }

}

Other Important Apex Interview Questions

Here are other important Apex interview questions in Salesforce that are often overlooked but can be crucial during interviews.

Apex Developer Interview Questions

1. How do you debug Apex code in Salesforce?
2. What tools do you use for Apex development?
3. How do you handle large data volumes in triggers?
4. How do you make asynchronous calls in Apex?

Async Apex Interview Questions

Here are asynchronous Apex interview questions to help you understand how to handle background processes and improve performance in Salesforce.

1. What is the difference between @future and Queueable Apex?
2. When would you use batch Apex instead of a future method?
3. How do you monitor asynchronous jobs in Salesforce?
4. What is the purpose of System.schedule() in Apex?

Note – Asynchronous Apex in Salesforce interview questions often include topics like future methods, batch Apex, queueable Apex, and scheduled jobs.

Scenario Based Apex Trigger Interview Questions

Here are Apex Trigger scenario-based questions that test your ability to write efficient and error-free trigger logic in real Salesforce use cases.

1. How would you design a trigger to update contact records when an account field changes?
2. How do you handle multiple triggers on the same object?
3. How do you avoid hitting SOQL limits inside a trigger?
4. How would you restrict trigger execution based on user profile?

Note – Apex trigger interview questions scenario based often include topics like before/after triggers, trigger context variables, recursion handling, and bulk-safe coding practices.

Also Read - Top 15+ Salesforce Interview Questions On Triggers

Apex Class Interview Questions

1. What is an Apex class and how is it structured?
2. What is the use of constructors in Apex classes?
3. How do you pass data between classes in Apex?
4. How do you make a class testable in Salesforce?

Batch Apex Interview Questions

Here are some commonly asked Batch Apex interview questions.

1. What are the three main methods in a Batch Apex class?
2. How do you schedule a batch job in Salesforce?
3. Can you run multiple batches in parallel?
4. What are the common limits in Batch Apex?

Queueable Apex Interview Questions

1. What is Queueable Apex and how is it different from future methods?
2. How do you chain multiple Queueable jobs?
3. Can you call a Queueable job from a trigger?
4. How do you test Queueable Apex in unit tests?

Tips to Prepare for Apex Interview

Here are some great tips to help you prepare for your Apex interview. 

• Revise key Apex concepts like triggers, classes, and governor limits.
• Practice writing bulk-safe code with collections.
• Learn to debug using Developer Console and system logs.
• Write test classes with proper coverage and assertions.
• Understand async processing: future, batch, and queueable.
• Go through real scenario-based questions, not just theory.

Also Read - Top 15+ Salesforce CPQ Interview Questions and Answers

Wrapping Up

These 25+ Apex interview questions and answers give you a solid start for Salesforce developer roles. Keep practising real-world scenarios and writing clean, efficient code. Stay updated with new features in Apex.

Looking for Apex jobs in India? Check out Hirist – an online job portal made for tech professionals like you. Find top roles and apply with ease.

Also Read - Top 30+ Salesforce Interview Questions and Answers

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