JarCastingDokka 
Dokka is a documentation engine for Kotlin, performing the same function as javadoc for Java. Just like Kotlin itself, Dokka fully supports mixed-language Java/Kotlin projects. It understands standard Javadoc comments in Java files and KDoc comments in Kotlin files, and can generate documentation in multiple formats including standard Javadoc, HTML and Markdown.
Using Dokka
Full documentation is available at https://kotlin.github.io/dokka/1.4.32/
Using the Gradle plugin
Note: If you are upgrading from 0.10.x to a current release of Dokka, please have a look at our migration guide
The preferred way is to use plugins block.
build.gradle.kts:
plugins {
id("org.jetbrains.dokka") version "1.4.32"
}
repositories {
mavenCentral()
}
The plugin adds dokkaHtml, dokkaJavadoc, dokkaGfm and dokkaJekyll tasks to the project.
Applying plugins
Dokka plugin creates Gradle configuration for each output format in the form of dokka${format}Plugin:
dependencies {
dokkaHtmlPlugin("org.jetbrains.dokka:kotlin-as-java-plugin:1.4.32")
}
You can also create a custom Dokka task and add plugins directly inside:
val customDokkaTask by creating(DokkaTask::class) {
dependencies {
plugins("org.jetbrains.dokka:kotlin-as-java-plugin:1.4.32")
}
}
Please note that dokkaJavadoc task will properly document only single jvm source set
To generate the documentation, use the appropriate dokka${format} Gradle task:
./gradlew dokkaHtml
Please see the Dokka Gradle example project for an example.
We encourage users to create their own plugins and share them with the community on official plugins list.
Android
Make sure you apply Dokka after com.android.library and kotlin-android.
buildscript {
dependencies {
classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlin_version}")
classpath("org.jetbrains.dokka:dokka-gradle-plugin:${dokka_version}")
}
}
repositories {
mavenCentral()
}
apply(plugin= "com.android.library")
apply(plugin= "kotlin-android")
apply(plugin= "org.jetbrains.dokka")
dokkaHtml.configure {
dokkaSourceSets {
named("main") {
noAndroidSdkLink.set(false)
}
}
}
Multi-module projects
For documenting Gradle multi-module projects, you can use dokka${format}Multimodule tasks.
tasks.dokkaHtmlMultiModule.configure {
outputDirectory.set(buildDir.resolve("dokkaCustomMultiModuleOutput"))
}
DokkaMultiModule depends on all Dokka tasks in the subprojects, runs them, and creates a toplevel page with links to all generated (sub)documentations
Using the Maven plugin
The Maven plugin does not support multi-platform projects.
Documentation is by default generated in target/dokka.
The following goals are provided by the plugin:
dokka:dokka- generate HTML documentation in Dokka format (showing declarations in Kotlin syntax)dokka:javadoc- generate HTML documentation in Javadoc format (showing declarations in Java syntax)dokka:javadocJar- generate a .jar file with Javadoc format documentation
Applying plugins
You can add plugins inside the dokkaPlugins block:
<plugin>
<groupId>org.jetbrains.dokka</groupId>
<artifactId>dokka-maven-plugin</artifactId>
<version>${dokka.version}</version>
<executions>
<execution>
<phase>pre-site</phase>
<goals>
<goal>dokka</goal>
</goals>
</execution>
</executions>
<configuration>
<dokkaPlugins>
<plugin>
<groupId>org.jetbrains.dokka</groupId>
<artifactId>kotlin-as-java-plugin</artifactId>
<version>${dokka.version}</version>
</plugin>
</dokkaPlugins>
</configuration>
</plugin>
Please see the Dokka Maven example project for an example.
Using the Command Line
To run Dokka from the command line, download the Dokka CLI runner. To generate documentation, run the following command:
java -jar dokka-cli.jar <arguments>
You can also use a JSON file with dokka configuration:
java -jar <dokka_cli.jar> <path_to_config.json>
Output formats
Dokka documents Java classes as seen in Kotlin by default, with javadoc format being the only exception.
html- HTML format used by defaultjavadoc- looks like JDK's Javadoc, Kotlin classes are translated to Javagfm- GitHub flavored markdownjekyll- Jekyll compatible markdown
If you want to generate the documentation as seen from Java perspective, you can add the kotlin-as-java plugin to the Dokka plugins classpath, eg. in Gradle:
dependencies{
implementation("...")
dokkaGfmPlugin("org.jetbrains.dokka:kotlin-as-java-plugin:${dokka-version}")
}
FAQ
If you encounter any problems, please see the FAQ.
