I’m building a Gradle Plugin with Kotlin, in one of the features I’m using Ktor and Coroutines. The plugin must to be included as classpath in third part projects.
Problem comes when I’m trying to use the Plugin in another project, I'm getting:
Caused by: java.lang.NoClassDefFoundError: kotlin/coroutines/Continuation on the consumer project.
I tried to isolate the Coroutines dependencies and apply transitive dependencies for Ktor but no success.
I have seen too different solutions(https://github.com/Kotlin/kotlinx.coroutines/issues/430) like applying ShadowJar to build a FatJar but maybe I’m missing something in the configuration. Once I apply the Shadow Plugin the jar is about 62Mb, even applying minimize size of the jar is 12MB.
The basic conf(based on the samples of Kotlin-DSL) of the plugin would be:
plugins {
`kotlin-dsl`
`maven-publish`
kotlin("jvm") version "1.3.10"
id("com.github.johnrengelman.shadow") version "4.0.3"
}
gradlePlugin {
plugins {
register("greet-plugin") {
id = "greet"
implementationClass = "GreetPlugin"
}
}
dependencies {
api("io.ktor:ktor-client-okhttp:1.0.1")
}
}
val sourcesJar by tasks.registering(Jar::class) {
classifier = "sources"
from(sourceSets.main.get().allSource)
}
val shadowJar: ShadowJar by tasks
shadowJar.apply {
baseName = "test"
classifier = ""
minimize()
}
The complete example is here:
https://github.com/cdsap/testPluginCoroutinesProblem
A more detailed error
java.lang.NoClassDefFoundError: kotlin/coroutines/Continuation
at io.ktor.client.engine.okhttp.OkHttp.create(OkHttp.kt:8)
at io.ktor.client.HttpClientKt.HttpClient(HttpClient.kt:36)
at io.ktor.client.HttpClientKt.HttpClient$default(HttpClient.kt:33)
at GreetPlugin.apply(GreetPlugin.kt:26)
at GreetPlugin.apply(GreetPlugin.kt:12)
I expect the plugin will build properly the coroutines dependency within Ktor and don't have big jar as dependency.
Related
I'm setting up a multi-module Gradle project based on Kotlin for the JVM. Since the root project does not contain any code, the Kotlin plugin should only be applied to subprojects.
build.gradle.kts (root project)
plugins {
kotlin("jvm") version "1.6.20" apply false
}
subprojects {
apply(plugin = "kotlin")
group = "com.example"
repositories {
mavenCentral()
}
dependencies {}
kotlin {
jvmToolchain {
check(this is JavaToolchainSpec)
languageVersion.set(JavaLanguageVersion.of(11))
}
}
}
Trying to set a toolchain causes the build to fail at the kotlin {...} extension:
Unresolved reference. None of the following candidates is applicable because of receiver type mismatch:
public fun DependencyHandler.kotlin(module: String, version: String? = ...): Any defined in org.gradle.kotlin.dsl
public fun PluginDependenciesSpec.kotlin(module: String): PluginDependencySpec defined in org.gradle.kotlin.dsl
It works fine if I copy the extension definition to each subproject build script, but why isn't it available in the main script?
This is one of my favourite things to fix in Gradle, and really shows off the flexibility that's possible (as well as demonstrating why Gradle can be complicated!)
First I'll give a bit of background info on the subprojects {} DSL, then I'll show how to fix your script, and finally I'll show the best way to share build logic with buildSrc convention plugins. (Even though it's last, I really recommend using buildSrc!)
Composition vs Inheritance
Using allprojects {} and subprojects {} is really common, I see it a lot. It's more similar to how Maven works, where all the configuration is defined in a 'parent' build file. However it's not recommended by Gradle.
[A], discouraged, way to share build logic between subproject is cross project configuration via the subprojects {} and allprojects {} DSL constructs.
Gradle Docs: Sharing Build Logic between Subprojects
(It's probably common because it's easy to understand - it makes Gradle work more like Maven, so each project inherits from one parent. But Gradle is designed for composition. Further reading: Composition over inheritance: Gradle vs Maven)
Quick fix: 'Unresolved reference'
The error you're seeing is basically because you haven't applied the Kotlin plugin.
plugins {
kotlin("jvm") version "1.6.20" apply false // <- Kotlin DSL won't be loaded
}
The kotlin { } configuration block is a very helpful extension function that is loaded when the Kotlin plugin is applied. Here's what it looks like:
/**
* Configures the [kotlin][org.jetbrains.kotlin.gradle.dsl.KotlinJvmProjectExtension] extension.
*/
fun org.gradle.api.Project.`kotlin`(configure: Action<org.jetbrains.kotlin.gradle.dsl.KotlinJvmProjectExtension>): Unit =
(this as org.gradle.api.plugins.ExtensionAware).extensions.configure("kotlin", configure)
// (note: this is generated code)
So if we don't have the extension function, we can just call configure directly, and thus configure the Kotlin extension.
subprojects {
// this is the traditional Gradle way of configuring extensions,
// and what the `kotlin { }` helper function will call.
configure<org.jetbrains.kotlin.gradle.dsl.KotlinJvmProjectExtension> {
jvmToolchain {
check(this is JavaToolchainSpec)
languageVersion.set(JavaLanguageVersion.of(11))
}
}
// without the Kotlin Gradle plugin, this helper function isn't available
// kotlin {
// jvmToolchain {
// check(this is JavaToolchainSpec)
// languageVersion.set(JavaLanguageVersion.of(11))
// }
// }
}
However, even though this works, using subprojects {} has problems. There's a better way...
buildSrc and Convention Plugins
buildSrc is, basically, a standalone Gradle project, the output of which we can use in the main project's build scripts. So we can write our own custom Gradle plugins, defining conventions, which we can selectively apply to any subproject in the 'main' build.
(This is the key difference between Gradle and Maven. In Gradle, a subproject can be configured by any number of plugins. In Maven, there's only one parent. Composition vs Inheritance!)
The Gradle docs have a full guide on setting up convention plugins, so only I'll briefly summarise the solution here.
1. Set up ./buildSrc
Create a directory named buildSrc in your project root.
Because buildSrc is a standalone project, create a ./buildSrc/build.gradle.kts and ./buildSrc/settings.gradle.kts files, like usual for a project.
In ./buildSrc/build.gradle.kts,
apply the kotlin-dsl plugin
add dependencies on Gradle plugins that you want to use anywhere in your project
// ./buildSrc/build.gradle.kts
plugins {
`kotlin-dsl` // this will create our Gradle convention plugins
// don't add the Kotlin JVM plugin
// kotlin("jvm") version embeddedKotlinVersion
// Why? It's a long story, but Gradle uses an embedded version of Kotlin,
// (which is provided by the `kotlin-dsl` plugin)
// which means importing an external version _might_ cause issues
// It's annoying but not important. The Kotlin plugin version below,
// in dependencies { }, will be used for building our 'main' project.
// https://github.com/gradle/gradle/issues/16345
}
val kotlinVersion = "1.6.20"
dependencies {
implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion")
}
Note that I've used the Maven repository coordinates for the Kotlin Gradle plugin, not the plugin ID!
You can also add other dependencies into ./buildSrc/build.gradle.kts if you like. If you wanted to parse JSON in a build script, then add a dependency on a JSON parser, like kotlinx-serialization.
2. Create a convention plugin
Create your Kotlin JVM convention that you can apply to any Kotlin JVM subproject.
// ./buildSrc/src/main/kotlin/my/project/convention/kotlin-jvm.gradle.kts
package my.project.convention
plugins {
kotlin("jvm") // don't include a version - that's provided by ./buildSrc/build.gradle.kts
}
dependencies {
// you can define default dependencies, if desired
// testImplementation(kotlin("test"))
}
kotlin {
jvmToolchain {
check(this is JavaToolchainSpec)
languageVersion.set(JavaLanguageVersion.of(11))
}
}
}
Don't forget to add the package declaration! I've forgotten it a few times, and it causes errors that are hard to figure out.
3. Applying the convention plugin
Just like how Gradle plugins have IDs, so do our convention plugins. It's the package name + the bit before .gradle.kts. So in our case the ID is my.project.convention.kotlin-jvm
We can apply this like a regular Gradle plugin...
// ./subprojects/my-project/build.gradle.kts
plugins {
id("my.project.convention.kotlin-jvm")
}
(Convention plugins can also import other convention plugins, using id("..."))
Also, since we're using Kotlin, there's an even nicer way. You know how there are included Gradle plugins, like java and java-library. We can import our convention plugins the same way!
// ./subprojects/my-project/build.gradle.kts
plugins {
// id("my.project.convention.kotlin-jvm")
my.project.convention.`kotlin-jvm` // this works just like id("...") does
}
Note the backticks around the plugin ID - they're needed because of the hyphen.
(caveat: this non-id("...") way doesn't work inside buildSrc, only in the main project)
Result
Now the root ./build.gradle.kts can be kept really clean and tidy - it only needs to define the group and version of the project.
Because we're using convention plugins and not blanket subprojects, each subproject can be specialised and only import convention plugins that it needs, without repetition.
Site note: sharing repositories between buildSrc and the main project
Usually you want to share repositories between buildSrc and the main project. Because Gradle plugins are not specifically for projects, we can write a plugin for anything, including settings.gradle.kts!
What I do is create a file with all the repositories I want to use...
// ./buildSrc/repositories.settings.gradle.kts
#Suppress("UnstableApiUsage") // centralised repository definitions are incubating
dependencyResolutionManagement {
repositories {
mavenCentral()
jitpack()
gradlePluginPortal()
}
pluginManagement {
repositories {
jitpack()
gradlePluginPortal()
mavenCentral()
}
}
}
fun RepositoryHandler.jitpack() {
maven("https://jitpack.io")
}
(the name, repositories.settings.gradle.kts, isn't important - but naming it *.settings.gradle.kts should mean IntelliJ provides suggestions, however this is bugged at the moment.)
I can then import this as a plugin in the other settings.gradle.kts files, just like how you were applying the Kotlin JVM plugin to subprojects.
// ./buildSrc/settings.gradle.kts
apply(from = "./repositories.settings.gradle.kts")
// ./settings.gradle.kts
apply(from = "./buildSrc/repositories.settings.gradle.kts")
I have a gradle kotlin project, and I'm generating a kotlin file from a Rust project, so it ends up in a totally different place with no gradle project structure, etc.
How do I import this file into my gradle project?
It has its own package but it's a completely standalone file. This is my gradle file:
rootProject.name = "my_project"
include("app")
It's a desktop project, NOT android.
My build.gradle.kts:
plugins {
// Apply the org.jetbrains.kotlin.jvm Plugin to add support for Kotlin.
id("org.jetbrains.kotlin.jvm") version "1.5.31"
// Apply the application plugin to add support for building a CLI application in Java.
application
}
repositories {
// Use Maven Central for resolving dependencies.
mavenCentral()
}
dependencies {
// Align versions of all Kotlin components
implementation(platform("org.jetbrains.kotlin:kotlin-bom"))
// Use the Kotlin JDK 8 standard library.
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
// This dependency is used by the application.
implementation("com.google.guava:guava:30.1.1-jre")
// Use the Kotlin test library.
testImplementation("org.jetbrains.kotlin:kotlin-test")
// Use the Kotlin JUnit integration.
testImplementation("org.jetbrains.kotlin:kotlin-test-junit")
}
application {
// Define the main class for the application.
mainClass.set("my_project.ffi.AppKt")
}
Adding the following code to your build.gradle.kts should do the trick (tested with Gradle 7.3.2):
// TODO: replace this dummy task with the task from your Rust project which
// generates the Kotlin source directory. Make sure that the generated
// directory (with the Kotlin file(s)) is the task output directory.
val rustTask by tasks.registering(Copy::class) {
// To test this, I had simply put a Kotlin file into this "somewhere"
// directory.
from("somewhere")
into(temporaryDir)
}
sourceSets {
main {
java {
srcDir(rustTask)
}
}
}
tasks {
compileKotlin {
dependsOn(rustTask)
}
}
So, we’re simply adding the generated sources as an additional source directory to the default SourceSet which is consumed by the compileKotlin task. In addition, we make sure that the sources are generated before compileKotlin runs.
I'm having a gradle script to execute Kotlin code with the gradle application plugin:
plugins {
id 'org.jetbrains.kotlin.jvm' version '1.4.10'
id 'application'
}
repositories {
mavenCentral()
}
dependencies {
implementation platform("org.jetbrains.kotlin:kotlin-bom")
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
// Some other deps
}
sourceSets {
main.kotlin.srcDirs += '.'
}
application {
mainClassName = 'MainKt'
}
What I would like to achieve: During the docker container startup I would like to load all the necessary dependencies with gradle build --build-cache command and be able to run gradle run --offline in the offline mode when the image is ready.
What do I have at the moment: I'm getting No cached version of org.jetbrains.kotlin:kotlin-scripting-compiler-embeddable:1.4.10 available for offline mode. error because plugin dependencies are not being cached during the build phase.
Any ideas what I can do to force gradle to cache not only listed dependencies but also dependencies required by plugins?
Adding the plugin dependency to the dependency list explicitly helped me to resolve this issue:
dependencies {
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
implementation "org.jetbrains.kotlin:kotlin-scripting-compiler-embeddable" // <-- this solves the problem
// Some other deps
}
I hope this answer will be helpful! Although the use-case is pretty narrow.
I'm writing a custom Gradle plugin using Kotlin. The goal is to apply and configure certain plugins within this custom plugin. Consumers should only need to apply the custom plugin and be all set.
The problem:
I want to apply these two kotlin plugins (and other plugins) in the custom plugin (which can be applied like this normally in a Gradle build script):
kotlin("jvm") version "1.4.10"
kotlin("plugin.spring") version "1.4.10"
But when applying them from within my own plugin a couple of things goes wrong.
The jar task is not found. I get this complaint in the project consuming my plugin.
The contents of the dependencies section, e.g api, implementation etc are also causing errors, like if Gradle doesn't understand what they are.
I can, in the consuming project however, simply add the line below to the build script to get the jar task back, and make dependencies work again:
kotlin("jvm") version "1.4.10"
I also wrote a sort of debug function in the consuming Gradle build, just to see what plugins are applied. They all print true when I apply only my own plugin (or add kotlin-jvm to the script manually). Which seems to me like my own plugin is doing its job.
open class GreetingTask : DefaultTask() {
#TaskAction
fun greet() {
println("hello from GreetingTask")
println(project.pluginManager.hasPlugin("org.springframework.boot"))
println(project.pluginManager.hasPlugin("io.spring.dependency-management"))
println(project.pluginManager.hasPlugin("com.github.ben-manes.versions"))
println(project.pluginManager.hasPlugin("org.jetbrains.kotlin.jvm"))
println(project.pluginManager.hasPlugin("org.jetbrains.kotlin.plugin.spring"))
println(project.pluginManager.hasPlugin("java"))
}
}
My apply method so far in my plugin:
override fun apply(project: Project) {
configureRepositories(project)
configureTesting(project)
configureJava(project)
configureSpringBoot(project)
configureSpringDependencyManagement(project)
configureKotlin(project)
configureVersions(project)
configurePublishing(project)
}
And for setting up Kotlin:
private fun configureKotlin(project: Project) {
project.pluginManager.apply("org.jetbrains.kotlin.jvm")
project.pluginManager.apply("org.jetbrains.kotlin.plugin.spring")
project.tasks.withType(KotlinCompile::class.java).configureEach { task ->
task.kotlinOptions.freeCompilerArgs = listOf("-Xjsr305=strict")
task.kotlinOptions.jvmTarget = "11"
}
}
All the other configureXYZ seems to work out fine.
I solved it. The problem was how I applied the plugin.
This does NOT work:
build.gradle.kts
buildscript {
repositories {
mavenLocal()
gradlePluginPortal()
}
dependencies {
classpath("com.praqma:demo:1.0.0")
}
}
apply(plugin = "com.praqma.demo.DemoPlugin")
This does work:
settings.gradle.kts
pluginManagement {
repositories {
mavenLocal()
gradlePluginPortal()
}
}
build.gradle.kts
plugins {
id("gradle.demoPlugin") version "0.0.1-SNAPSHOT"
}
I wanted to create a new project that should be a desktop application. For this purpose, I have selected Kotlin language and TornadoFX framework. I have installed the TornadoFXplugin and created a new Ttornadofx-gradle-project. The base setup made by Intellij was successful but I have encountered a problem. When I wanted to run the generated project it failed. The project cannot resolve the java fx. I have dug through the web and found nothing that would fix the problem. The error log that I receive after the failed build is:
HAs anyone faces the same issue? How can I get rid of it?
I have installed the JDK 11 and set it up to the build config and I still receive the problem:
java.lang.UnsupportedClassVersionError: org/openjfx/gradle/JavaFXPlugin has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
Is there a change that I have missed something in the middle?
It looks like you are running the TornadoFX project with Java 11 or 12.
It also looks like the TornadoFX plugin is intended for Java 1.8, but it is not advised what to do with Java 11+.
Since Java 11, JavaFX is no longer part of the JDK.
You can read all about getting JavaFX as a third party dependency into your project here: https://openjfx.io/openjfx-docs/, and since you are using Gradle, this section will be helpful: https://openjfx.io/openjfx-docs/#gradle.
I've just installed the Tornado plugin, and created a project, using JDK 12.0.1. I've also updated the gradle-wrapper.properties file to use Gradle 5.3-bin as the default 4.4 doesn't work with Java 11+.
If I run it, I get the same errors:
e: /.../src/main/kotlin/com/example/demo/app/Styles.kt: (3, 8): \
Unresolved reference: javafx
e: /.../src/main/kotlin/com/example/demo/app/Styles.kt: (18, 13): \
Cannot access class 'javafx.scene.text.FontWeight'. Check your module classpath for missing or conflicting dependencies
...
Basically these errors indicate that JavaFX is not found. The Tornado plugin wasn't expecting this.
Solution
There is an easy solution to make this work: add the JavaFX gradle plugin to the build, so it deals with the JavaFX part.
According to the plugin's repository, all you need to do is edit the build.gradle file and add:
buildscript {
ext.kotlin_version = "1.2.60"
ext.tornadofx_version = "1.7.17"
ext.junit_version = "5.1.0"
repositories {
mavenLocal()
mavenCentral()
maven {
setUrl("https://plugins.gradle.org/m2/")
}
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
classpath "org.junit.platform:junit-platform-gradle-plugin:1.1.0"
// Add JavaFX plugin:
classpath 'org.openjfx:javafx-plugin:0.0.7'
}
}
apply plugin: "kotlin"
apply plugin: "application"
apply plugin: "org.junit.platform.gradle.plugin"
// Apply JavaFX plugin:
apply plugin: 'org.openjfx.javafxplugin'
// Add the JavaFX version and required modules:
javafx {
version = "12.0.1"
modules = [ 'javafx.controls', 'javafx.fxml' ]
}
...
And this is it, refresh your project, the IDE should recognize all the JavaFX classes.
If you modify the default MainView.kt like:
class MainView : View("Hello TornadoFX \n with JavaFX "
+ System.getProperty("javafx.version")) {
override val root = hbox {
label(title) {
addClass(Styles.heading)
}
}
}
you should be able to run it:
This answer is for those who wish to use Gradle Kotlin DSL.
An example of minimal build.gradle.kts:
plugins {
kotlin("jvm") version "1.4.0-rc"
application
id("org.openjfx.javafxplugin") version "0.0.9"
}
application { mainClassName = "com.example.MyApp" }
repositories {
mavenCentral()
jcenter()
maven("https://dl.bintray.com/kotlin/kotlin-eap")
}
dependencies {
// Kotlin standard library
implementation(kotlin("stdlib-jdk8"))
// TornadoFX dependency
implementation("no.tornado:tornadofx:1.7.20")
}
// JavaJX module to include
javafx { modules = listOf("javafx.controls", "javafx.fxml", "javafx.graphics") }
// Set Kotlin/JVM target versions
tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
kotlinOptions.jvmTarget = "11" // or higher
kotlinOptions.languageVersion = "1.4"
}
// Be sure to use lates Gradle version
tasks.named<Wrapper>("wrapper") { gradleVersion = "6.6" }
For a full working example, check out GitHub repository
Please note that it also works with JDK 13 and 14
i'm recieved this error when download Kodein-Samples and trying to run tornadofx sample under Java11/12 and JavaFX13.
java.lang.UnsupportedClassVersionError: org/openjfx/gradle/JavaFXPlugin has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
The solution was is quite simple: i'm only comment another modules in settings.gradle (because the error occurred in some other module). Unfortunately, after the launch the application generates an error when trying to edit the record. I haven't dealt with it yet.
so my build.gradle.kts looks like this:
import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
val kodeinVersion: String by rootProject.extra
plugins {
kotlin("jvm")
application
id("org.openjfx.javafxplugin") version "0.0.8"
}
repositories {
jcenter()
maven(url = "https://dl.bintray.com/kodein-framework/Kodein-DI/")
}
application {
mainClassName = "org.kodein.samples.di.tornadofx.KodeinApplication"
}
javafx {
version = "13"
modules = mutableListOf("javafx.controls", "javafx.fxml", "javafx.base", "javafx.media")
}
tasks.withType<KotlinCompile> {
kotlinOptions.jvmTarget = JavaVersion.VERSION_11.toString()
}
dependencies {
implementation(kotlin("stdlib-jdk8"))
implementation("no.tornado:tornadofx:1.7.19")
implementation("org.kodein.di:kodein-di-generic-jvm:$kodeinVersion")
implementation("org.kodein.di:kodein-di-conf:$kodeinVersion")
implementation("org.kodein.di:kodein-di-framework-tornadofx-jvm:$kodeinVersion")
}
i made fork for this example with changes: https://github.com/ibelozor/Kodein-Samples