ClassNotFoundException for mixed java and kotlin code when running from command line

Question

I have mixed Java & Kotlin code in a demo project which I want to run from command line. For only java, I am able to run the program with java -jar foo.jar but when I use any class from Kotlin code, it generates java.lang.NoClassDefFoundError: kotlin/jvm/internal/Intrinsics

I have tried different solutions and checked the jar file. It contains both the classes but I guess kotlin-runtime is missing from jar.

Here is build.gradle file

plugins {
    id 'java-library'
    id 'org.jetbrains.kotlin.jvm'
}

sourceSets {
    main.java.srcDirs += 'src/main/kotlin/'
    test.java.srcDirs += 'src/test/kotlin/'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    testImplementation 'junit:junit:4.12'
}

jar {
    manifest {
        attributes 'Main-Class': 'com.mallaudin.App'
    }
    from {
        configurations.compile.collect {
            it.isDirectory()? it: zipTree(it)
        }
    }
}

Content of generated jar file

.
├── com
│   └── mallaudin
│       ├── App.class
│       └── User.class
└── META-INF
    ├── basics.kotlin_module
    └── MANIFEST.MF

Content of MANIFEST.MF

Manifest-Version: 1.0
Main-Class: com.mallaudin.App

Exception I get when I run jar form command line

allaudin@geek ~/Desktop/KotlinLab (master) $ java -jar basics/build/libs/basics.jar 
Exception in thread "main" java.lang.NoClassDefFoundError: kotlin/jvm/internal/Intrinsics
    at com.mallaudin.User.<init>(User.kt)
    at com.mallaudin.App.main(App.java:5)
Caused by: java.lang.ClassNotFoundException: kotlin.jvm.internal.Intrinsics
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:190)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
    ... 2 more

Can you please post the dependencies part of your build.gradle? I assume the kotlin runtime is not defined as a compile time dependency. — Erik Pragt
– Erik Pragt, Commented Dec 16, 2018 at 1:26
@ErikPragt I think the same but I have added the dependency. I don't know what's going on. — m_allaudin
– m_allaudin, Commented Dec 16, 2018 at 6:42
This is probably a pretty clear writeup" stackoverflow.com/questions/44493378/… — Erik Pragt
– Erik Pragt, Commented Dec 17, 2018 at 6:19

Louis Jacomet · Accepted Answer · 2018-12-17 09:33:08Z

3

The issue is in the way you build your fat jar. While you use the more recent and recommended implementation scope for your dependencies, you are only adding to the fat jar the content of the compile configuration.

You should replace the configuration to be used in the fat jar by runtimeClasspath which is the full set of runtime components.

That is:

jar {
  manifest {
    attributes 'Main-Class': 'com.mallaudin.App'
  }
  from {
    configurations.runtimeClasspath.collect {
      it.isDirectory()? it: zipTree(it)
    }
  }
}

Have a look at the documentation to understand the different dependency configurations for a java project.

answered Dec 17, 2018 at 9:33

Louis Jacomet

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Comments

m_allaudin · Accepted Answer · 2018-12-16 16:26:08Z

0

So, I have found a solution. In build.gradle file I have replaced implementation configuration with compile and it works now. I believe it should work with implementation too but it doesn't. Now the jar looks like this

.
├── com
├── kotlin
├── META-INF
└── org

edited Dec 16, 2018 at 16:26

answered Dec 16, 2018 at 11:48

m_allaudin

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5 Comments

Erik Pragt Over a year ago

Hi, I'm glad it works now, but that's what I said in my previous comment already ;-)

m_allaudin Over a year ago

But why it doesn't work with implementation? Do you have any idea?

Erik Pragt Over a year ago

I'm pretty sure it will work with implementation too, but then you need to change this line: configurations.compile to also include implementation: configurations.implementation. Right now, you only include compilation scope, cause that was the 'old' way of doing things.

m_allaudin Over a year ago

configurations.implementation is not allowed. I have checked it already.

Maroun Over a year ago

I'm having the same problem. Switching from implementation to api didn't help.

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