Installing Kotlin
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Installing the JDK First
Kotlin compiles to JVM bytecode, so a Java Development Kit must be installed before the Kotlin compiler will work. Most systems use JDK 11 or newer; running java -version confirms one is already present.
Note: If java -version fails, install a JDK (e.g. Temurin or OpenJDK) before installing Kotlin.
Example: Installing the JDK First
# Linux/macOS (SDKMAN)
sdk install java 21-tem
# Windows
# Download JDK from https://adoptium.net and run the installer⚠️ Run this command in your terminal.
Installing kotlinc
The standalone Kotlin compiler, kotlinc, can be installed with a package manager: SDKMAN's sdk install kotlin on Linux/macOS, Homebrew's brew install kotlin on macOS, or Chocolatey's choco install kotlin on Windows. Each gives you the kotlinc command globally.
Example: Installing kotlinc
# Linux/macOS (SDKMAN)
sdk install kotlin
# macOS (Homebrew)
brew install kotlin
# Windows (Chocolatey)
choco install kotlin⚠️ Run this command in your terminal.
Verifying the Installation
After installing, run kotlinc -version in a terminal to confirm the compiler is on your PATH and see which Kotlin version you have. This step catches PATH problems early, before you write any real code.
Note: Run kotlinc -version in your terminal -- it should print something like info: kotlinc-jvm 1.9.x.
Example: Verifying the Installation
kotlinc -version⚠️ Run this command in your terminal.
Compiling and Running a File
Once installed, a .kt file is compiled with kotlinc file.kt -include-runtime -d app.jar and then run with java -jar app.jar. The -include-runtime flag bundles the Kotlin standard library into the jar so it runs anywhere a JVM is available.
Note: kotlinc file.kt alone (no -d) produces .class files you can run with kotlin MainKt instead.
Example: Compiling and Running a File
kotlinc hello.kt -include-runtime -d hello.jar
java -jar hello.jar⚠️ Run this command in your terminal.
- Forgetting that Kotlin needs a Java Development Kit (JDK) installed first, since Kotlin compiles to JVM bytecode.
- Trying to write Kotlin code before verifying the install with
kotlinc -version, then debugging phantom errors caused by a missing compiler. - Assuming Kotlin can only be installed through Android Studio and not knowing standalone installers (SDKMAN, Homebrew, Chocolatey) exist.
- Kotlin requires a JDK to run, since it compiles to JVM bytecode.
- The compiler can be installed via SDKMAN (Linux/macOS), Homebrew (macOS), or Chocolatey (Windows), among other options.
kotlinc -versionconfirms the compiler is installed and shows which version you have.- You do not need Android Studio to install or use the Kotlin compiler for plain command-line programs.
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