# Android를 위한 Kotlin 언어 기초 (Android)

> var vs val, null safety, data classes, when 표현식, extension functions, scope functions 및 Kotlin의 기본 개념

- 24 면접 질문
- Junior
- [면접 질문: Android](https://sharpskill.dev/ko/technologies/android/interview-questions.md)

## 1. Kotlin에서 'var'와 'val'의 차이점은 무엇인가요?

**답변**

'var'는 가변(수정 가능) 변수를 선언하고, 'val'은 불변(읽기 전용) 변수를 선언합니다. 불변성을 촉진하고 버그를 방지하기 위해 기본적으로 'val'을 사용하는 것이 권장됩니다.

## 2. Kotlin에서 타입 뒤의 '?' 연산자는 무엇을 의미하나요?

**답변**

'?' 연산자는 변수가 null을 포함할 수 있음을 나타냅니다. 예를 들어, 'String?'은 변수가 String 또는 null이 될 수 있음을 의미합니다. 이것은 Kotlin의 null safety 시스템의 기초입니다.

## 3. Kotlin의 '!!' 연산자는 무엇을 하나요?

**답변**

'!!' 연산자(not-null assertion)는 컴파일러가 nullable 값을 non-null로 처리하도록 강제합니다. 값이 null이면 NullPointerException이 발생합니다. 값이 null이 아니라고 확신할 때만 사용하세요.

## 21개 추가 질문 이용 가능

- Kotlin의 엘비스 연산자 '?:'는 무엇에 사용되나요?
- Kotlin의 data class란 무엇인가요?

무료로 가입하기: https://sharpskill.dev/ko/login

## 기타 Android 면접 주제

- [Android 기초](https://sharpskill.dev/ko/technologies/android/interview-questions/android-fundamentals.md): 24개 질문, Junior
- [Android UI 및 리소스](https://sharpskill.dev/ko/technologies/android/interview-questions/android-ui-and-resources.md): 30개 질문, Junior
- [Android 생명주기](https://sharpskill.dev/ko/technologies/android/interview-questions/android-lifecycle.md): 30개 질문, Junior
- [Android 내비게이션](https://sharpskill.dev/ko/technologies/android/interview-questions/android-navigation.md): 26개 질문, Junior
- [Android 데이터 관리](https://sharpskill.dev/ko/technologies/android/interview-questions/android-data-management.md): 29개 질문, Junior
- [Android 네트워킹](https://sharpskill.dev/ko/technologies/android/interview-questions/android-networking.md): 29개 질문, Junior
- [Android 테스트](https://sharpskill.dev/ko/technologies/android/interview-questions/android-testing.md): 28개 질문, Junior
- [Android Gradle](https://sharpskill.dev/ko/technologies/android/interview-questions/android-gradle.md): 26개 질문, Junior
- [Room Database](https://sharpskill.dev/ko/technologies/android/interview-questions/android-room-database.md): 25개 질문, Mid-Level
- [백그라운드 작업](https://sharpskill.dev/ko/technologies/android/interview-questions/android-background-work.md): 18개 질문, Mid-Level
- [Jetpack Compose](https://sharpskill.dev/ko/technologies/android/interview-questions/android-compose.md): 28개 질문, Mid-Level
- [권한 및 기기 기능](https://sharpskill.dev/ko/technologies/android/interview-questions/android-permissions-and-device.md): 21개 질문, Mid-Level
- [Android용 Firebase](https://sharpskill.dev/ko/technologies/android/interview-questions/android-firebase.md): 23개 질문, Mid-Level
- [Android MVVM Architecture](https://sharpskill.dev/ko/technologies/android/interview-questions/android-mvvm-architecture.md): 18개 질문, Mid-Level
- [Android 네트워킹 고급](https://sharpskill.dev/ko/technologies/android/interview-questions/android-networking-advanced.md): 13개 질문, Mid-Level
- [Kotlin 컬렉션과 연산자](https://sharpskill.dev/ko/technologies/android/interview-questions/android-kotlin-collections-operators.md): 20개 질문, Mid-Level
- [Kotlin Coroutines와 Flow](https://sharpskill.dev/ko/technologies/android/interview-questions/android-kotlin-coroutines-flow.md): 20개 질문, Mid-Level
- [Android 의존성 주입](https://sharpskill.dev/ko/technologies/android/interview-questions/android-dependency-injection.md): 15개 질문, Mid-Level
- [Android MVI Architecture](https://sharpskill.dev/ko/technologies/android/interview-questions/android-mvi-architecture.md): 17개 질문, Mid-Level
- [Android Clean Architecture](https://sharpskill.dev/ko/technologies/android/interview-questions/android-clean-architecture.md): 21개 질문, Senior
- [Android Compose 고급](https://sharpskill.dev/ko/technologies/android/interview-questions/android-compose-advanced.md): 17개 질문, Senior
- [Android Performance and Monitoring](https://sharpskill.dev/ko/technologies/android/interview-questions/android-performance-monitoring.md): 13개 질문, Senior
- [Android Security and Privacy](https://sharpskill.dev/ko/technologies/android/interview-questions/android-security-privacy.md): 18개 질문, Senior
- [Android CI/CD and Release](https://sharpskill.dev/ko/technologies/android/interview-questions/android-cicd-release.md): 15개 질문, Senior
- [Android UX and Form Factors](https://sharpskill.dev/ko/technologies/android/interview-questions/android-ux-form-factors.md): 18개 질문, Senior
- [Android Testing Advanced](https://sharpskill.dev/ko/technologies/android/interview-questions/android-testing-advanced.md): 18개 질문, Senior

---

Source: SharpSkill (https://sharpskill.dev), tech interview preparation for your real stack.
HTML version of this page: https://sharpskill.dev/ko/technologies/android/interview-questions/android-kotlin-language-essentials