Kotlin Compilation and Tooling

Kotlin compiles to JVM bytecode by default, meaning every Kotlin file produces .class files that run on any standard Java Virtual Machine. This allows Kotlin and Java files to coexist freely in the same project, calling each other's APIs without any bridging layer. The Kotlin compiler (kotlinc) can also target JavaScript for frontend development and LLVM-based native binaries for platforms such as iOS, macOS, Linux, and Windows through Kotlin/Native. Kotlin Multiplatform Mobile (KMM) leverages this to share business logic between Android and iOS apps. Build tooling support is first-class: both Gradle and Maven provide official Kotlin plugins, and IntelliJ IDEA (as well as Android Studio, which is based on it) ships with deep Kotlin integration including real-time inspections, refactoring tools, and a REPL.

Example

// build.gradle.kts (Kotlin DSL) — minimal Android/JVM project
plugins {
    kotlin("jvm") version "1.9.22"
    application
}

repositories {
    mavenCentral()
}

dependencies {
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3")
    testImplementation(kotlin("test"))
}

application {
    mainClass.set("MainKt")   // top-level main() lives in MainKt
}

tasks.test {
    useJUnitPlatform()
}

// Kotlin script (.kts) — runnable without compilation step
// kotlinc -script hello.kts
val items = listOf("apple", "banana", "cherry")
items.forEachIndexed { index, item ->
    println("${index + 1}. $item")
}

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