Everything this plugin does is to provide the Kotlin stdlib and all common kotlinx libraries at runtime. This way you won't have to shade these Kotlin dependencies into your .jar file. This avoids conflicts and reduces the file size.
Add this dependency to your Gradle project:
compileOnly("net.axay:spigot-language-kotlin:VERSION")
Make sure that you declare the dependency in your plugin.yml:
depend: [ spigot-language-kotlin ]
And add the plugin (which you can download from the releases page) to your plugins
directory.
(Optional) If you are using the Gradle shadow plugin anyways, you can exclude all Kotlin dependencies from the shadow task by configuring it this way:
shadowJar {
dependencies {
exclude { it.moduleGroup == "org.jetbrains.kotlin" || it.moduleGroup == "org.jetbrains.kotlinx" }
}
}