Kotlin Language Essentials for Android

var vs val, null safety, data classes, when expressions, extension functions, scope functions and fundamental Kotlin concepts

24 면접 질문·

Junior

What is the difference between 'var' and 'val' in Kotlin?

답변

'var' declares a mutable (modifiable) variable, while 'val' declares an immutable (read-only) variable. It's recommended to use 'val' by default to promote immutability and avoid bugs.

What does the '?' operator after a type mean in Kotlin?

답변

The '?' operator indicates that the variable can contain null. For example, 'String?' means the variable can be a String or null. This is the basis of Kotlin's null safety system.

What does the '!!' operator do in Kotlin?

답변

The '!!' operator (not-null assertion) forces the compiler to treat a nullable value as non-null. If the value is null, a NullPointerException is thrown. Only use when you're certain the value is not null.

Kotlin Language Essentials for Android

What is the difference between 'var' and 'val' in Kotlin?

답변

What does the '?' operator after a type mean in Kotlin?

답변

What does the '!!' operator do in Kotlin?

답변

What is the Elvis operator '?:' used for in Kotlin?

What is a data class in Kotlin?

기타 Android 면접 주제

Android Fundamentals

Android UI and Resources

Android Lifecycle

Android Navigation

Android Data Management

Android Networking

Android Testing

Android Gradle

Room Database

Background Work

Jetpack Compose

Permissions and Device Features

Firebase for Android

Android MVVM Architecture

Advanced Android Networking

Kotlin Collections and Operators

Kotlin Coroutines and Flow

Android Dependency Injection

Android MVI Architecture

Android Clean Architecture

Android Compose Advanced

Android Performance and Monitoring

Android Security and Privacy

Android CI/CD and Release

Android UX and Form Factors

Android Testing Advanced

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