Automation (RPA)
Software Design
JS Frameworks
.Net Stack
Java Stack
Django Stack
Cloud Computing
Mobile Development
SAP Modules
BIG Data
BI and Data Analytics
Web Technologies
All Interviews

Top 32 Kotlin Interview Questions and Answers

12/Sep/2020 | 7 minutes to read


Here is a List of essential Kotlin Interview Questions and Answers for Freshers and mid level of Experienced Professionals. All answers for these Kotlin questions are explained in a simple and easiest way. These basic, advanced and latest Kotlin questions will help you to clear your next Job interview.

Kotlin Interview Questions and Answers

These questions are targeted for Kotlin Programming Language. You must know the answers of these frequently asked basic and advanced kotlin interview questions to clear the android developer interview.

1. What is Kotlin. Why use it?

Kotlin is a general purpose cross-platform, open-source, statically typed programming language. Kotlin provides a combination of the object oriented and functional programming features.
Why Kotlin? Kotlin make developers happy because it is:

  • Concise - Using kotlin reduces a lot of boilerplate code.
  • Safe - It's type safe and avoids a lot of errors such as type casting errors, null pointer exceptions etc.
  • Interoperable - Kotlin is designed to fully leverage the libraries for JVM, Android and JavaScript (browser).
  • Tool-friendly - Kotlin can be used with any Java IDE or built from the command line.

2. What are the advantages and disadvantages of Kotlin?

3. How will you compare Kotlin vs Java?

4. Differentiate fold and reduce in Kotlin?

5. Explain the difference between val and var in Kotlin.

6. In Kotlin, How to deal with nullable values?

7. How to get a random number in Kotlin?

8. How to initialize Kotlin's Mutable list to empty Mutable list?

9. What is the equivalent of the static method of Java in Kotlin?

10. Explain Lambda (function) in Kotlin.

11. How Property Initialization works in Kotlin? Explain by lazy vs lateinit.

12. Explain Lazy Initialization and Late Initialization.

13. How to initialize a reference variable in Kotlin?

14. How to create a variable without initialization in Kotlin?

15. How to check that a lateinit variable has been initialized?

16. Why does the Kotlin compiler require explicit initialization of var property?

17. Explain delegates in Kotlin.

18. How to access val variable in the inner method?

19. What is the difference between List and Array types?

20. What is the difference between val and const in Kotlin?

21. Explain In-line function in Kotlin.

22. Explain string templates in kotlin.

23. Explain format in kotlin string templates?

24. What is data class in kotlin?

25. What resources are available to learn kotlin?

For kotlin tutorials you can visit kotlin tutorial

Some General Interview Questions for Kotlin

1. How much will you rate yourself in Kotlin?

When you attend an interview, Interviewer may ask you to rate yourself in a specific Technology like Kotlin, So It's depend on your knowledge and work experience in Kotlin.

2. What challenges did you face while working on Kotlin?

This question may be specific to your technology and completely depends on your past work experience. So you need to just explain the challenges you faced related to Kotlin in your Project.

3. What was your role in the last Project related to Kotlin?

It's based on your role and responsibilities assigned to you and what functionality you implemented using Kotlin in your project. This question is generally asked in every interview.

4. How much experience do you have in Kotlin?

Here you can tell about your overall work experience on Kotlin.

5. Have you done any Kotlin Certification or Training?

It depends on the candidate whether you have done any Kotlin training or certification. Certifications or training are not essential but good to have.


We have covered some frequently asked Kotlin Interview Questions and Answers to help you for your Interview. All these Essential Kotlin Interview Questions are targeted for mid level of experienced Professionals and freshers.
While attending any Kotlin Interview if you face any difficulty to answer any question please write to us at Our IT Expert team will find the best answer and will update on the portal. In case we find any new Kotlin questions, we will update the same here.