This resource provides valuable guidance for Kotlin developers preparing for job interviews. It comprises an extensive list of over 50 common interview questions, each paired with concise and memorable answers. The answers are presented in active voice, emphasizing clarity and readability. Aspiring Kotlin developers can use this material to deepen their understanding of critical concepts, best practices, and language features, enabling them to excel in Kotlin-related job interviews. Topics covered include Kotlin fundamentals, null safety, coroutines, functional programming, extension functions, and more. Whether you’re new to Kotlin or seeking to sharpen your skills, this material is an excellent aid for interview preparation.
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What is Kotlin, and why is it used?
- Kotlin is a modern, statically-typed programming language that is widely used for Android app development. Its concise syntax and safety features make it a preferred choice for developers.
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Explain the differences between Kotlin and Java.
- Kotlin offers concise code, null safety, and more expressive syntax compared to Java. It reduces boilerplate code and provides improved type inference.
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How do you declare a variable in Kotlin?
- In Kotlin, you declare a variable using the ‘val’ (immutable) or ‘var’ (mutable) keyword, followed by the variable name and its type, e.g., val age: Int = 30.
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What is a data class in Kotlin, and why is it useful?
- A data class in Kotlin is used to create classes that are primarily used to store data. It automatically generates hashCode(), equals(), and toString() methods, making data handling more convenient.
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Explain the ‘when’ expression in Kotlin.
- ‘When’ is used for conditional branching in Kotlin. It’s a concise way to replace the traditional ‘switch’ statement, and it can be used for various data types.
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What is a Kotlin extension function, and why use it?
- A Kotlin extension function allows you to add new functions to existing classes without modifying their source code. It’s useful for enhancing functionality without inheritance.
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How does Kotlin handle null safety, and what are the nullable types?
- Kotlin uses the ? symbol to indicate nullable types. This enforces safe handling of null values, reducing the chance of null pointer exceptions.
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Explain the concept of ‘coroutines’ in Kotlin.
- Coroutines are lightweight threads that allow for asynchronous and non-blocking programming in Kotlin. They simplify concurrency management and make code more readable.
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What is a higher-order function in Kotlin, and why is it important?
- A higher-order function can accept other functions as parameters or return them as results. This feature is essential for functional programming and simplifies code.
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How do you perform string interpolation in Kotlin?
- String interpolation in Kotlin is done using the ‘$’ symbol followed by the variable name or expression within a string, e.g., “Hello, $name!”
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Explain the use of ‘lateinit’ in Kotlin.
- ‘lateinit’ is used to declare non-nullable properties that are initialized later. It helps prevent null pointer exceptions by indicating that the property will be assigned before use.
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What is the purpose of the ‘apply’ function in Kotlin?
- The ‘apply’ function is used to configure the properties of an object in a builder-like manner and returns the modified object. It enhances code readability.
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How do you create and handle exceptions in Kotlin?
- Exceptions in Kotlin are created using the ‘throw’ keyword and caught using ‘try-catch’ blocks. This ensures error handling and program stability.
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Explain the ‘sealed’ class in Kotlin.
- A ‘sealed’ class is used to represent restricted hierarchies. It ensures that all subclasses are known, which is useful in when expressions for exhaustive checks.
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What is the purpose of the ‘with’ function in Kotlin?
- The ‘with’ function is used to simplify access to the properties and functions of an object. It eliminates the need to repeat the object’s name within a block.
