KoJni

A Gradle Plugin for generating JNI header files.

The problem

Since JDK 8+, javah (a tool for generating JNI header files) isn't included. The replacement is javac -h. However, javac runs only on Java source code; while javah would work on .class files. As a result from the change, other JVM languages (such as Kotlin) were left without a solution for generating JNI headers.

The Solution

KoJni is a gradle plugin that handles JNI header generation for you, via the generateJni task.

Current status

KoJni 1.0.0 is stable. See the roadmap for more info about current capabilities and future versions.

Usage / Configuration

KoJni is intended to work with the new native plugins, with the native lib as a subproject (see this issue).

Example file structure:

.
|   build.gradle(.kts)
|   settings.gradle(.kts)
+---example
|   |   build.gradle(.kts)
|   \---src
|       \---main
|           +---cpp
|           \---headers
\---src
    \---main
        \---kotlin

Root build.gradle.kts for this example:

plugins {
  kotlin("jvm") version "1.4.21" // kotlin plugin
  id("io.github.starlight.KoJni") version "1.0.0"
}
repositories {
  mavenCentral()
  jcenter()
}
jni {
  libName = "example" // name of jni lib folder 
  tasks.generateJni.configure {
    dependsOn("compileKotlin") // depends on JVM compilation
  }
}