In today's fast-paced tech industry, staying relevant is critical. This is where Kotlin comes into play. Developed by JetBrains, Kotlin is a modern programming language that aims to make developers more productive, reduce errors, and improve code readability. Since Google officially endorsed Kotlin for Android development, many companies have adopted it for their projects. In fact, according to the 2021 Stack Overflow Developer Survey, Kotlin is the fourth most loved programming language and the fifth most wanted language by developers. Whether you're a seasoned developer or just starting, preparing for Kotlin interview questions can open up exciting opportunities for your career growth.
In this Blog, we have included the most recent and frequently asked Kotlin Interview Questions and Answers that have been further categorized as per the criteria mentioned above.
Ans: Kotlin is a statically-typed cross-platform programming language employed mainly for developing concise, compressed, expressive, and secure apps. JetBrains created it in the year 2011.
Ans: The essential aspects of Kotlin include extension functions, null security lambdas, coroutines and interoperability in Java.
Ans: Kotlin can be compared with Java since it's a JVM-based programming language and considerably more straightforward to read than Java codes. Kotlin has many features that Java does not have, like extensions and null safety functions.
Ans: The most common data types are Int, Long, Double, Float, Char, Boolean and String.
Ans: A nullable type holds either a value belonging to a specific data type or an empty value. You use the question mark (?) following the data type to declare a nullable type.
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Ans: Intelligent cast feature lets the compiler automatically convert a variable into the non-nullable kind if it is able to establish that the variable cannot have a value that is null.
Ans: Extension functions are extensions included in an existing program without modifying the class. This lets you create new features to classes that you do not possess control over.
Ans: A lambda function is a type of function that can be transferred as a variable and utilized as an argument to various functions. It is often utilized to construct functional-style codes.
Ans: A higher-order function takes the parameters of another program and returns the function in return. This permits more flexibility and efficient code.
Ans: Coroutines can be used to write asynchronous code that is simpler to understand and maintain than traditional callback-based codes. Coroutines allow you to create code that appears as if it's synchronous, but actually, it runs asynchronously in the background.
Ans: Elvis operator (? :) is a shorthand method for null values. This returns the amount that is left if it's null and the opposite value in case that value is not null.
Ans: A safe caller (?.) is a shorthand term for null values. It lets you safely access methods or properties on an object without throwing an exception for null pointers when the object is not null.
Ans: An array is a series of values that spans two ends. A progression is a set of values with an exact interval between them.
Ans: The with function lets you perform multiple functions on an object without repeating the object's name. It accepts objects as parameters, and lambda is a block of code to run on that object.
Ans: The function applies identically to the with function but will return the item it was used on instead of the outcome of lambda. This lets you connect several calls on the exact object.
Ans: The term "object" refers to a singular instance of an object class. It is created lazy and is accessible by the object's name.
Ans: Inline functions are functions that are expanded during compile time instead of invoked during execution. This improves performance in specific scenarios.
Ans: A reified type parameter can be described as an element of the type parameter accessible during execution. It is usually employed along with inline functions to carry out type checks while running.
Ans: Higher-order extensions are a function that takes a function's parameter and returns the function in return. This lets you write more flexible and robust code.
Ans: A coroutine scope is a means to manage coroutines as well as their lifecycles. It defines the context within which coroutines are started and also provides a method to end all coroutines within this context.
Ans: Launch() can be used to start an execution plan that is running in the background but does not produce a result, and the async() is utilized to initiate an execution that produces the Deferred object, which is used to get the output that the Coroutine has produced.
Ans: The term "flow" refers to a set of asynchronous values that can be released quickly. It's like streams or is observable in different languages.
Ans: The suspend feature is a feature which can be stopped and resumed at a later point. It is usually utilized along with coroutines in order to execute asynchronous tasks.
Ans: A property delegate is a method to customize the behaviour of property accessors. It lets you define specific get behaviour and set it for the property.
Ans: Lazy properties are only created at the time of first access. This improves performance in certain circumstances.
Ans: A delegated property has accessors provided by an object called a delegate. It lets you define specific behaviour for property accessors.
Ans: A property extension adds to an existing object without altering the class. This lets you add additional properties to classes you have no control over.
Ans: Elvis operator can be represented with the? Symbol. It is used to give an alternative value in the event the nullable variable is not null.
Ans: A safe call is represented with the?. Symbol. It can be employed to access the functions or properties of an object that is nullable. If the object is null, the expression returns null instead of throwing a Null Pointer Exception.
Ans: A lambda expression is a function not defined with an identifier and can be transferred around as variables. It is frequently utilized together with higher-order functions, as well as Kotlin's functional programming capabilities.
Ans: The lateinit method allows you to define a variable to be created later, whereas lazy initialization can be used to declare a variable that will be initialized upon first use. Lazy initialization is thread-safe, but lateinit isn't.
Ans: A suspend lambda can be described as a lambda expression which is identified with the modifier suspend. It is a good choice with coroutines to perform Asynchronous operations.
Ans: A sealed interface is comparable to a closed class; however, it is only implemented by classes inside one file. It is typically employed to create a limited range of interfaces.
Ans: A projection can be used to define a generic parameter as being either covariant or invariant. This permits more flexibility and accurate type-checking.
Ans: The term "platform type" refers to a class that isn't explicitly designated as non-nullable or nullable. It is commonly employed in conjunction using Java code that doesn't explicitly declare nullability.
Ans: Function calls that use the infix modifier are called using the infix modifier and are named using the infix notation (e.g. FunctionName: b), and normal function calls utilize the standard syntax (e.g. functionName(a, b)). Infix function calls only be used with only one parameter.
Ans: A typealias can be utilized to give a different name for a particular type. It is utilized to make code accessible and avoid lengthy declarations of types.
Ans: suspendCoroutine is a function of higher order which is used to stop the current Coroutine and then start another one. It is typically utilized to perform low-level Coroutine operations.
Ans: Primary constructors are defined within the header of the class and serve to define the characteristics that the class has. Secondary constructors can be defined in the body of the class and serve to offer additional methods to initialize the class.
Ans: A typealias projection is a method to project an alias type onto a particular type parameter. It is a method to produce less readable and concise code.
1. Research the company and their use of Kotlin in its tech stack.
2. Practice Kotlin coding challenges and algorithms to improve your problem-solving skills.
3. Review Kotlin syntax and its features to ensure familiarity during the interview.
4. Understand the differences between Kotlin and Java to highlight the benefits of using Kotlin.
5. Prepare examples of Kotlin projects you have worked on and be ready to discuss your contributions.
6. Familiarize yourself with popular Kotlin frameworks and their use cases.
7. Be prepared to explain the benefits of using Kotlin for Android development.
8. Review the Kotlin standard library and know how to use common functions.
9. Research common Kotlin interview questions and prepare responses.
10. Showcase your teamwork skills by discussing collaboration on Kotlin projects.
11. Be ready to discuss the benefits and drawbacks of using Kotlin versus other programming languages.
12. Stay up-to-date on Kotlin updates and new features to showcase your interest in the language.
The visibility modifier can be used to establish a function's extent, class or variable. The four types of visibility are private, internal, protected and public.
An enclosed class is a type of class which can only be extended by classes that are part of this same directory. It is usually employed in conjunction with expressions to make a limited subclass.
The term "companion object" refers to an object connected to a specific class and can be utilized to record static methods as well as properties.
The data class can be described as a type of class which is designed to hold information. It automatically generates useful functions like equals() as well as hashCode() and even toString() in accordance with its properties.
Conclusion:
Preparing for a Kotlin interview requires both understanding of the language's syntax and knowledge of its application in real-world scenarios. The Kotlin interview questions and answers provided in this blog serve as a valuable resource to help you prepare for your next Kotlin interview. It's important to take the time to familiarize yourself with the language's features, such as its null safety and extension functions, and to practice implementing them in code. Additionally, reviewing common Kotlin interview questions and practising answering them concisely and clearly is useful.
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