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Kotlin Online Test

The Kotlin Online Test uses scenario-based and code tracing MCQ questions to evaluate a candidate's ability to use Kotlin basics (Variables, Strings), Kotlin Collections (List, Map, Set, Iterators), and Kotlin OOPs (classes, inheritance, interfaces) to develop null-safe, concise and readable Kotlin code. The test has coding questions to evaluate hands-on Kotlin programming skills.

Customized Based On:

  • Experience/ difficulty level
  • Multiple skills in 1 assessment
  • Job description/ role requirements

Covered Topics:

Kotlin basics (Variables; Strings; Functions)
Kotlin collections (Lists; Set; Maps; Iterators)
Object-Oriented Programming (Classes; Inheritance)
Reading and Writing Files
Standard functions (apply; let; with; run)
Extension functions
Working with APIs
Adding dependencies
Asynchronous Programming (Coroutines)
See full list
Singapore government logo

The hiring managers felt that through the technical questions that they asked during the panel interviews, they were able to tell which candidates had better scores, and differentiated with those who did not score as well. They are highly satisfied with the quality of candidates shortlisted with the Adaface screening.

Human Resources Manager

Singapore Government

reduction in screening time

Sample Kotlin Online Test Questions

These are just a small sample from our library of 10,000+ questions. The actual questions on this Kotlin Online Test will be non-googleable.

🧐 Question🔧 Skill💪 Difficulty⌛ Time
twoWheeler Interface
What will the following code output?
KotlinEasy3 min

How to use the Adaface Kotlin Online Test

Start screening candidates within minutes with the ready-to-go Kotlin Online Test

1. Choose the most appropriate test for your role

2. Start inviting candidates to complete the assessment

3. Receive real time notifications and shortlist the best candidates

Customize the Adaface Kotlin Online Test according to your job description

1. Get a custom assessment from our library of 500+ skills within 48 hours

2. Start inviting candidates to complete the assesment

3. Receive real time notifications and shortlist the best candidates

Adaface Kotlin Online Test is trusted by enterprises worldwide

Morgan Stanley
SG Government
Ernst and Young
Optimum Solutions
United Nations
Love Bonito

About the Adaface Kotlin Assessment Test

Evaluate Kotlin technical and coding skills with Adaface skills assessment platform powered by an intelligent chatbot


Variables & nullable types (null safety)
Conditionals: if and when
Loops: for and while
Functional programming
Web requests
Object-oriented programming
Creating classes and instances
String templates
Nullable values and null checks
Type checks and automatic casts
Data classes
Sealed classes
Generics: in, out, where
Nested and inner classes
Enum and inline classes
Object expressions and declarations

Recommended Roles:

Kotlin Developer
Android Kotlin Devloper
Android Developer - Java / Kotlin
Software Developer 1 (Kotlin)
Mobile Application Developer
Senior Kotlin Developer

Why You Should Use This Kotlin Online Test

The Kotlin Online test helps recruiters and hiring managers identify qualified candidates from a pool of resumes, and helps in taking objective hiring decisions. It reduces the administrative overhead of interviewing too many candidates and saves expensive engineering time by filtering out unqualified candidates.

The Adaface Kotlin test screens candidates for the typical skills recruiters look for in a Kotlin developer:

  • Kotlin fundamentals (variables, strings, operators)
  • Nullability
  • Collections (list, set, map)
  • Lambdas and higher-order functions (common higher-order functions)
  • Object-oriented programming principles (Classes, objects, inheritance, polymorphism, abstraction, encapsulation)
  • Class types (Data, Enum, Sealed, Nested)
  • Standard functions and extension functions
  • Coroutines and asynchronous programming
  • File I/O
  • Exceptions Handling

The Kotlin Online test is designed to test for Kotlin fundamentals and hands-on coding skills. If you would like to test Android skills, then we design a custom test to evaluate Kotlin and Android skills in the same assessment. You can review our Android test to get a sense of our Android questions.

How is the test customized for Senior Kotlin Developers?

The questions will test advanced topics for tests aimed at senior developers. Here are some topics that we use to create advanced Kotlin questions:

  • How to convert Java code into Kotlin
  • Understand how Java and Kotlin programs interoperate
  • Advanced OOP (Interface Classes, Abstract Classes, Generic Classes, Enums in Kotlin)
  • Advanced collections (MapOf, Arrayof, MutableList)
  • Asynchronous programming techniques (Threading, Callbacks, Futures, promises etc)
  • Reactive extensions and Coroutines

Distribution Of Test Scores

The actual score distribution will vary based on your candidate pipeline quality, but you should typically expect ~20% of the candidates to do well on Adaface assessments.

The score distribution for our assessments follow the normal curve. This is a good sign- standardized tests like SAT and GRE follow the normal distribution (bell curve).

Status quo assessments typically have the exact opposite of the bell curve (too many candidates getting close to 0, too many candidates getting close to 100 and too few candidates in the middle). This is typically because they focus on theoretical questions or trick questions, which are very binary in nature- either you know the trick/ theory or you don’t.

How Adaface Is Different

Adaface conversational assessments are reflective of on-the-job skills and see an 86% completion rate as compared to ~50% for traditional assessment platforms.



Theoretical questions/ puzzles

Feels like a test

One-size-fits-all assessments




Questions for on-the-job skills




Kotlin Online Test FAQs

Can I evaluate Kotlin and Android in the same test?

Yes. We support testing multiple skills in the same test. You can review our standard Android test to get a sense of what kind of questions will be included to test Android skills. The final test will include MCQ questions to evaluate Kotlin, Android and coding questions to evaluate Kotlin.

Can I have Kotlin as an optional skill in the Android test?

Yes. We design custom chat flows where a few skills can be optional. For Android roles, typically we design tests where candidates are given a choice to choose their preferred programming language between Java and Kotlin. The bot will ask questions only on the chosen programming language. The coding questions can be restricted to desired programming languages. In this case, the candidate can choose between Java and Kotlin to write the code.

What is a custom assessment?

Every role is different and requires a custom assessment to identify top candidates efficiently. Adaface subject matter experts understand your job description/ role requirements and pick the most relevant questions from our library of 10000+ questions to create a technical assessment that helps you find the qualified candidates in your candidate pipeline quickly. All custom assessments are set up based on the job description, role requirements, must-have skills, experience level and salary range within a maximum of 48 hours and you will get an email notification once it goes live.

Check out a sample assessment here (no credit card required).

Can I combine multiple skills into one custom assessment?

Yes, absolutely. Custom assessments are set up based on your job description, and will include questions on all must-have skills you specify.

How is Adaface different from other assessment tools?

We believe that status quo tech assessment platforms are not a fair way for companies to evaluate engineers because they focus on trick questions/ puzzles/ niche algorithms. We started Adaface to help companies find great engineers by assessing on-the-job skills required for a role. Read more about why we started Adaface.

Here's what's different with Adaface:

  • High quality non-googleable questions that test for on-the-job skills as opposed to theoretical knowledge.
  • A friendly conversational assessment with a chatbot, instead of sending a "test" to a candidate. This translates to a higher completion rate. Adaface assessments (86% candidate completion rate), as opposed to traditional tests (40-50% candidate completion rate)
  • Customized assessments for 700+ skills at different experience levels.

Do you have any anti-cheating or proctoring features in place?

We have the following anti-cheating features in place:

  • Web proctoring
  • Webcam proctoring
  • Plagairism detection
  • Non-googleable questions
  • Secure browser

Read more about the proctoring features.

How do I interpret test scores?

The primary thing to keep in mind is that an assessment is an elimination tool, not a selection tool. A skills assessment is optimized to help you eliminate candidates who are not technically qualified for the role, it is not optimized to help you find the best candidate for the role. So the ideal way to use an assessment is to decide a threshold score (typically 55%, we help you benchmark) and invite all candidates who score above the threshold for the next rounds of interview.

What experience level can I use this test for?

Each Adaface assessment is customized to your job description/ ideal candidate persona (our subject matter experts will pick the right questions for your assessment from our library of 10000+ questions). This assessment can be customized for any experience level.

Does every candidate get the same questions?

Yes, it makes it much easier for you to compare candidates. Options for MCQ questions and the order of questions are randomized. We have anti-cheating/ proctoring features in place. In our enterprise plan, we also have the option to create multiple versions of the same assessment with questions of similar difficulty levels.

I'm a candidate. Can I try a practice test?

No. Unfortunately, we do not support practice tests at the moment. However, you can use our sample questions for practice.

What is the cost of using this test?

You can check out our pricing plans.

Can I get a free trial?

The platform is completely self-serve, so here's one way to proceed:

  • You can sign up for free to get a feel for how it works.
  • The free trial includes one sample assessment (Java/ JavaScript) that you will find in your dashboard when you sign up. You can use it to review the quality of questions, and the candidate experience of a conversational test on Adaface.
  • To review the quality of questions, you can also review our public questions for 50+ skills here.
  • Once you're convinced that you want to try it out with real assessments and candidates, you can pick a plan according to your requirements.

I just moved to a paid plan. How can I request a custom assessment?

Here is a quick guide on how to request a custom assessment on Adaface.

With Adaface, we were able to optimise our initial screening process by upwards of 75%, freeing up precious time for both hiring managers and our talent acquisition team alike!

Brandon Lee, Head of People, Love, Bonito

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