Kotin class java.lang.ClassNotFoundException

[at-tantv]

I built example project Kotlin Gradle but it showed error "class not found exception"

Exception in thread "main" java.lang.RuntimeException: java.lang.ClassNotFoundException: Cannot find implementation for org.mapstruct.example.kotlin.converter.PersonConverter
	at org.mapstruct.factory.Mappers.getMapper(Mappers.java:61)
	at org.mapstruct.example.kotlin.MainKt.main(Main.kt:10)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:567)
	at com.intellij.rt.execution.application.AppMainV2.main(AppMainV2.java:131)
Caused by: java.lang.ClassNotFoundException: Cannot find implementation for org.mapstruct.example.kotlin.converter.PersonConverter
	at org.mapstruct.factory.Mappers.getMapper(Mappers.java:75)
	at org.mapstruct.factory.Mappers.getMapper(Mappers.java:58)
	... 6 more

[filiphr]

Can you please tell us how you are building the project?

Asking because our CI is green. See https://github.com/mapstruct/mapstruct-examples/runs/767089987

[Jozott00]

I have the same problem using the Mapstruct-Kotlin-Maven example. I use Intellij as IDE.

Exception in thread "main" java.lang.RuntimeException: java.lang.ClassNotFoundException: Cannot find implementation for org.mapstruct.example.kotlin.converter.PersonConverter
	at org.mapstruct.factory.Mappers.getMapper(Mappers.java:61)
	at org.mapstruct.example.kotlin.MainKt.main(Main.kt:10)

[otoman]

Hi, same problem here... JDK 16, Kotlin 1.5.21, Maven, IntelliJ IDEA...

[otoman]

Problem is in KAPT incompatibility with newer versions of JDK https://youtrack.jetbrains.com/issue/KT-45545

[fire-papaya]

Facing the same problem with: JDK 11, Kotlin 1.43.2, MapStruct 1.5.0.Beta1, IntelliJ IDEA

My build.gradle

plugins {
    id 'java'
    ...
    id 'org.jetbrains.kotlin.jvm' version "1.4.32"
    id 'org.jetbrains.kotlin.plugin.spring' version "1.4.32"
    id 'org.jetbrains.kotlin.plugin.jpa' version "1.4.32"
    id "org.jetbrains.kotlin.kapt" version "1.4.32"
}

dependencies {
    ...
    implementation 'org.mapstruct:mapstruct:1.5.0.Beta1'
    annotationProcessor 'org.mapstruct:mapstruct-processor:1.5.0.Beta1'
    testAnnotationProcessor 'org.mapstruct:mapstruct-processor:1.5.0.Beta1'
}

tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
    kotlinOptions {
        freeCompilerArgs = ["-Xjsr305=strict"]
        jvmTarget = "11"
    }
}

Tried launching with org.gradle.jvmargs='--illegal-access=permit', result is the same

EDIT

changed dependencies part to:

dependencies {
    ...
    implementation 'org.mapstruct:mapstruct:1.5.0.Beta1'
    kapt 'org.mapstruct:mapstruct-processor:1.5.0.Beta1'
    kapt 'org.mapstruct:mapstruct-processor:1.5.0.Beta1'
}

And now it works, apologies for the confusion. org.gradle.jvmargs='--illegal-access=permit' is not required