How Kotlin compiles to JVM bytecode

Introduction

Kotlin code is turned into JVM bytecode so it can run on any device with a Java Virtual Machine. This makes Kotlin programs work on many platforms easily.

When you want to write Kotlin programs that run on Android devices.

When you want to use Kotlin with existing Java libraries and tools.

When you want your Kotlin code to run on any computer with Java installed.

When you want to build server applications using Kotlin that run on JVM servers.

Syntax

Kotlin

kotlinc MyProgram.kt -include-runtime -d MyProgram.jar
java -jar MyProgram.jar

kotlinc is the Kotlin compiler command.

-include-runtime adds the Kotlin runtime to the output jar so it can run standalone.

Examples

Compile Hello.kt to a jar file and run it with Java.

Kotlin

kotlinc Hello.kt -d Hello.jar
java -jar Hello.jar

Compile MyApp.kt including Kotlin runtime in the jar, so it runs without extra setup.

Kotlin

kotlinc MyApp.kt -include-runtime -d MyApp.jar
java -jar MyApp.jar

Sample Program

This simple Kotlin program prints a message. When compiled, it becomes JVM bytecode that the Java Virtual Machine can run.

Kotlin

fun main() {
    println("Hello from Kotlin JVM bytecode!")
}

Important Notes

The Kotlin compiler converts your Kotlin code into JVM bytecode, which is a set of instructions the Java Virtual Machine understands.

You can run the compiled Kotlin program anywhere Java runs, making Kotlin very flexible.

Using -include-runtime helps create a jar file that runs without needing to add Kotlin libraries separately.

Summary

Kotlin code is compiled into JVM bytecode to run on the Java Virtual Machine.

This allows Kotlin programs to work on many devices and platforms that support Java.

The Kotlin compiler command kotlinc creates the bytecode and packages it for running.