In Multiplatform project, I want to use main function inside jvmMain to test the library I’m working on, but when I’m trying to run this it returns an error Error: Could not find or load main class MainKt for following function in Main.kt
fun main() {
println("Hello World!")
}
I've got Main.kt file in a root directory of my module, but putting it under some package is also throwing this error.
I'm using Java 8 JDK:
Are there any additional steps I should make to be able to use main function?
EDIT:
I did additional checks and I found out that when in the project I have android target then in the jvm main function I’m getting this error above. When I’m creating a new project with exactly the same configuration, but without android target it’s working properly, main function compiles and it is printing a message.
Any guess what is causing this problem?
Related
I am unable to run a simple test project using the intellij plugin cursive. I am able to open a REPL without any problems and can even call functions defined in the core.clj file.
Running the project directly however yields this error message:
Error running 'new-project.core': failed to access class com.intellij.execution.impl.ProcessStreamsSynchronizer from class com.intellij.execution.impl.ConsoleViewRunningState (com.intellij.execution.impl.ProcessStreamsSynchronizer is in unnamed module of loader com.intellij.util.lang.UrlClassLoader #402f32ff; com.intellij.execution.impl.ConsoleViewRunningState is in unnamed module of loader com.intellij.ide.plugins.cl.PluginClassLoader #c9a79eb)
Intellij run configuration here. Changing How to run it and What to run does nothing.
Starting the project via the Leiningen tab yields the same error message.
There is an issue open about it.
https://github.com/cursive-ide/cursive/issues/2350
Also I tried to do lein run Let me know if this work for you.
Below is the basic ktor file which is running properly from IDE but I created a fat jar file with "mvn install" and running it throws below exception:
Exception in thread "main" java.lang.UnsupportedOperationException: Packages and file facades are not yet supported in Kotlin reflection. Meanwhile please use Java reflection to inspect this class: class com.tech.ApplicationKt
fun main(args: Array<String>){
embeddedServer(Netty, 8080){
routing{
get("/demo"){
call.respondText("Hello demo")
}
}
}.start(wait = true)
}
I tried executing jar on Java 11 and 8 but I am getting same exception.
I just tried this out by following the official guide on ktor.io for setup with maven.
Afterwards I followed https://ktor.io/servers/deploy/packing/fatjar.html#fat-jar-maven for the jar compilation.
I encountered 2 issues:
I first tried the install:install task from the IntelliJ Maven side bar, but actually you have to use the lifecycle methods install or just package.
I had to adjust the mainClass attribute of the maven assembly plugin to match that of my own, e.g path.to.your.package.ServerKt or whatever your file is called.
Once I fixed those two everything worked fine.
If you still have issues, please show us you build file.
I am learning Kotlin by doing Kotlin Koans int IntelliJ EduKotlin plugin (https://plugins.jetbrains.com/plugin/8186). While doing tasks and running them im this plugin is working, I am not able to create new Kotlin script and run it without this plugin.
Sample code in a file named Hello.kt:
fun hello() : String {
return "ok"
}
Then I create new run configuration derived from 'Kotlin script', set 'Working directory' to ProjectName/src folder (or ProjectName folder, same result) and IDE shows me a 'Could not find script file: Hello.kt' warning as in the screen below:
And indeed, while trying to run script I got following stacktrace:
"C:\Program Files\Java\jdk1.8.0_74\bin\java" -Dfile.encoding=windows-1250 -classpath C:\Users\myUser\.IdeaIC2016\config\plugins\Kotlin\kotlinc\lib\kotlin-compiler.jar;C:\Users\myUser\.IdeaIC2016\config\plugins\Kotlin\kotlinc\lib\kotlin-reflect.jar;C:\Users\myUser\.IdeaIC2016\config\plugins\Kotlin\kotlinc\lib\kotlin-runtime.jar org.jetbrains.kotlin.cli.jvm.K2JVMCompiler -script Hello.kt
exception: java.lang.RuntimeException: Failed to evaluate script: kotlin.KotlinNullPointerException
at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileScript(KotlinToJVMBytecodeCompiler.kt:263)
at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileAndExecuteScript(KotlinToJVMBytecodeCompiler.kt:212)
at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:181)
at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:49)
at org.jetbrains.kotlin.cli.common.CLICompiler.exec(CLICompiler.java:181)
at org.jetbrains.kotlin.cli.common.CLICompiler.exec(CLICompiler.java:138)
at org.jetbrains.kotlin.cli.common.CLICompiler.exec(CLICompiler.java:57)
at org.jetbrains.kotlin.cli.common.CLICompiler.doMainNoExit(CLICompiler.java:248)
at org.jetbrains.kotlin.cli.common.CLICompiler.doMain(CLICompiler.java:238)
at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler$Companion.main(K2JVMCompiler.kt:248)
at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.main(K2JVMCompiler.kt)
Caused by: kotlin.KotlinNullPointerException
at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileScript(KotlinToJVMBytecodeCompiler.kt:475)
... 10 more
Process finished with exit code 2
What more, the hello method is marked as never used. However, when I change file extension from .kt to .ktscript, then this method is marked as used, and the output from running code is following:
"C:\Program Files\Java\jdk1.8.0_74\bin\java" -Dfile.encoding=windows-1250 -classpath C:\Users\myUser\.IdeaIC2016\config\plugins\Kotlin\kotlinc\lib\kotlin-compiler.jar;C:\Users\myUser\.IdeaIC2016\config\plugins\Kotlin\kotlinc\lib\kotlin-reflect.jar;C:\Users\myUser\.IdeaIC2016\config\plugins\Kotlin\kotlinc\lib\kotlin-runtime.jar org.jetbrains.kotlin.cli.jvm.K2JVMCompiler -script Hello.kt
error: source file or directory not found: Hello.kt
Process finished with exit code 1
So my question is: what am I missing when trying to create and run Kotlin code in a standalone Kotlin script in IntelliJ?
A standalone Kotlin script file needs to have a .kts extension. If you rename your file, you also need to make sure that your run configuration is updated to refer to the new name of the file.
Also, if you create any file (a regular Kotlin file or a .kts file) which only contains a function, running the script will not produce any output, because the function will not be called. To see some output, you need to call the function in your script:
fun hello(): String {
return "ok"
}
println(hello())
The stacktrace that you saw is a bug in Kotlin.
I followed the Kotlin tutorial for eclipse here : Getting Started With Eclipse Luna
However, I'm running into this error:
Error: Could not find or load main class _DefaultPackage
Anyone who knows to get around this?
This was a severe bug (KT-10221) in automatic generation of Launch Configuration in plugin version 0.4.0. It was fixed in 0.5.0 so the recommendend way to workaround is to update plugin.
The source of the problem was that the plugin used an old pattern for generating name of the class for main function that had been abandoned by Kotlin compiler.
It's possible to workaround it by editing launch configuration (Eclipse Menu -> Run -> Run Configurations...) by hand and changing Main class field in Java Application group. If the file is named hello.kt with no package directive, as it is described in tutorial, than corrected string should be HelloKt.
If file has name other.kt with package my.tutorial than the Main Class should contain my.tutorial.HelloKt. You can read more about it in the section Package-Level Functions of Calling Kotlin From Java page.
I have been getting the same issue. And after putting the right compiler output path, it got resolved.
Go to Project -> Project Compiler output :
In the text box, fill this:
[Absolute Path]/{Project Name}/out
In my case I was having this problem while trying to run the program using the Application Gradle plugin. The problem was in the mainClassName property using single quotes instead of double ones
This didn't work:
mainClassName = 'demo.HelloWorldKt'
With double quotes, it works:
mainClassName = "demo.HelloWorldKt"
For me it worked after I installed the correct JDK. I first had JDK 11 but the tutorial I did was with JDK 8 so after I installed this and set it in the "installed JREs" options it found the main class without having any "mainClassName" or any other option in the build.gradle file.
For me, it worked in a fresh eclipse workspace. Possibly, the Kotlin eclipse plugin is not playing well with other plugins (in my case, PyDev).
I'm creating a Kotlin Application with JavaFX and I had this issue until I went to:
Run > Run Configurations > Java Application > Common
I unticked "Allocate console" and it fixed the issue.
I use intellij-idea to develop OpenFL application.
But, build failed with empty error message.
In Flash develop, build was succeeded, no errors.
and neko target project was succeeded in intellij-idea.
this is error screenshot.
and this is code of main class.
haxe package;
import openfl.display.Sprite;
class Main extends Sprite {
public function new () {
super ();
}
}
I google about this errors but I can't resolve this problem.
I think this is OpenFL bug about hxcpp.
And I wondering that on my other pc, build was succeeded.