Updated March 6, 2023
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Introduction to Kotlin Interview Questions and Answers
Kotlin is a general-purpose, open-source, statically typed programming language. It is used in developing server-side applications to write and execute expressive code. It supports the implementation of any host that runs on Java applications. Multiple platforms support Kotlin/Native programming languages like iOS, android, windows, Linux, etc.
To crack an interview related to kotlin in 2023, it is crucial to prepare for interview questions and answers related to it. While every interview and job position is different, knowing the top 10 kotlin interview questions and answers can help you stand out. It will give you the knowledge and confidence required to shine in the interview.
We have gathered a list of the most popular 2023 kotlin questions and answers to assist you in your interview preparation.
Part 1 – Basic Kotlin interview questions with answers
Q1. What is kotlin?
Answer:
Kotin is an open-source programming language based on JVM (Java Virtual Machine) platform. It is a combination of procedural and object-oriented programming (OOP) languages. The key frameworks associated with kotlin for server-side development are Spring, x, HTML, and Ktor. Kotlin is an excellent choice for developing android applications, server-side applications, and a variety of other applications. The important advantages of kotlin on android platforms are compatibility, performance, interoperability, footprint, compilation time, and learning curve.
Q2. How does Kotlin work?
Answer:
Kotlin runs on Java virtual machine for its execution. All kotlin code is converted into native code through the process of bytecode conversion and can also use other relative virtual machines. For example, When a Kotlin file named as Main.kt is obtained, it will ultimately become a class and the bytecode for that class will generate. Furthermore, the bytecode file will be named MainKt.class and will be executed by the JVM.
Q3. what are the features of Kotlin not available in Java?
Answer:
Some key features of Kotlin that are not available in Java are:
- Extension Functions
- Operator Overloading
- Smart casts
- Data classes
- Range expressions
- Null Safety
- Coroutines
- Companion Objects
Q4. What are the benefits of Kotlin?
Answer:
The benefits of Kotlin are as follows:
- The syntax resembles java and is easy to learn
- Kotlin is interoperable
- It is a functional language based on JVM
- It is an OOPs-based programming language
Q5. Which extension methods kotlin provides in the java.io.file list?
Answer:
Some extension methods kotlin provides are:
- bufferedReader(): Read file content into BufferedReader
- readBytes(): Read file content to ByteArray
- readText(): Read file content to a single String.
- forEachLine(): Read a file line by line in Kotlin.
- readLines(): Read lines in the file to List.
Part 2 – Advanced Kotlin interview questions with answers
Q6. What is the difference between const vs val?
Answer:
Both the variables declared with const and val are irreversible in nature. Keyword const is used at compile-time initialization whereas Keyword val is used at runtime initialization
Q7. What are the types of constructors in Kotlin?
Answer:
Primary and secondary constructors are the two main types of constructors available in Kotlin. Primary Constructors are defined especially in a class definition like a class header. Secondary Constructors are defined inside the class body. when using a secondary constructor, it is necessary to call the primary constructor. In the following example, the variables in the first line declared right after the constructor keyword is the primary constructor. The secondary constructor is the one declared within the body of the class.
class A constructor(var nme: String, var age: Int)
{ var designation: String = "Not Mentioned"class A constructor(var nme: String, var age: Int){
constructor (nme: String, age: Int, designation: String): this(name,age){
this.designation = designationQ8. Is there a possibility to migrate code from Kotlin to Java?
Answer:
The answer is yes. Jet BRAINS idea provides an inbuilt tool to address this migration purpose. Follow the below steps to convert the Kotlin source file to a java source file.
- Open the Kotlin project in the Andriod studio/Intellij IDEA.
- Select Tools > Kotlin > Show Kotlin Bytecode.
- Click on Decompile button to obtain java code from the bytecode.
Q9. Does Kotlin support primitive datatypes in Java?
Answer:
No, kotlin does not support primitive datatypes in java.
Q10. What are the important key modifiers in Kotlin?
Answer:
This is a list of key modifiers:
- public
- private
- protected
- interval
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