[kapt] An exception occurred: java.lang.NoClassDefFoundError: io/vertx/lang/rxjava/AbstractRxGenerator

When I was run compileKotlin task then I got this error: java.lang.NoClassDefFoundError: io/vertx/lang/rxjava/AbstractRxGenerator

build.gradle

buildscript {
    ext.kotlin_version = '1.2.70'
    ext.vertx_version = '3.6.0-SNAPSHOT'
    ext.arrow_version = '0.7.3'
    ext.mockk_version = '1.8.7'

    repositories {
        mavenCentral()
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'org.junit.platform:junit-platform-gradle-plugin:1.0.0'
    }
}

apply plugin: 'idea'
apply plugin: 'java'
apply plugin: 'kotlin'
apply plugin: 'kotlin-kapt'
apply plugin: 'org.jetbrains.kotlin.jvm'
apply plugin: 'org.junit.platform.gradle.plugin'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
    maven { url "https://dl.bintray.com/kotlin/exposed" }
    maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
}

dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
    compile("org.jetbrains.kotlin:kotlin-compiler-embeddable:$kotlin_version") {
        transitive = true
    }
    compile 'org.jetbrains.exposed:exposed:0.10.5'

    compile 'com.auth0:java-jwt:3.4.0'
    compile 'com.rabbitmq:amqp-client:5.4.1'
    compile 'com.microsoft.sqlserver:mssql-jdbc:7.0.0.jre8'
    compile 'com.fasterxml.jackson.module:jackson-module-kotlin:2.9.6'
    compile 'org.mvel:mvel2:2.4.2.Final'

    compile "io.vertx:vertx-web:$vertx_version"
    compile "io.vertx:vertx-core:$vertx_version"
    compile "io.vertx:vertx-lang-kotlin:$vertx_version"
    compile "io.vertx:vertx-lang-kotlin-coroutines:$vertx_version"
    compile "io.vertx:vertx-jdbc-client:$vertx_version"
    compile "io.vertx:vertx-rx-java2:$vertx_version"
    compile "io.vertx:vertx-rabbitmq-client:$vertx_version"
    compile "io.vertx:vertx-service-proxy:$vertx_version"
    compile "io.vertx:vertx-service-discovery:$vertx_version"
    compile "io.vertx:vertx-hazelcast:$vertx_version"
    compile "io.vertx:vertx-codegen:$vertx_version"
    kapt "io.vertx:vertx-codegen:$vertx_version:processor"

    compile "io.arrow-kt:arrow-core:$arrow_version"
    compile "io.arrow-kt:arrow-syntax:$arrow_version"
    compile "io.arrow-kt:arrow-typeclasses:$arrow_version"
    compile "io.arrow-kt:arrow-data:$arrow_version"
    compile "io.arrow-kt:arrow-instances-core:$arrow_version"
    compile "io.arrow-kt:arrow-instances-data:$arrow_version"
    kapt "io.arrow-kt:arrow-annotations-processor:$arrow_version"

    testCompile "io.mockk:mockk:$mockk_version"
    testCompile group: 'junit', name: 'junit', version: '4.12'
    testCompile 'org.junit.jupiter:junit-jupiter-api:5.1.1'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.1.1'
    testCompile "org.junit.platform:junit-platform-runner:1.3.0"
}

junitPlatform {
    platformVersion '1.0.0'

    filters {
        engines {
            include 'junit-jupiter', 'junit-vintage'
        }
    }

    logManager 'org.apache.logging.log4j.jul.LogManager'
}

compileKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

kotlin {
    experimental {
        coroutines "enable"
    }
}

jar{
    from sourceSets.main.allJava
}

sourceSets {
    main.resources.srcDir('config')
    main.java.srcDirs += 'src/main/java'
    main.java.srcDirs += 'src/main/kotlin'
    main.java.srcDirs += [file("$buildDir/generated/source/kapt/main")]
    test.java.srcDirs += 'src/test/kotlin'
}

Error log:

15:41:34: Executing task 'compileKotlin'...

> Task :wrapper

BUILD SUCCESSFUL in 0s
1 actionable task: 1 executed
> Task :kaptGenerateStubsKotlin UP-TO-DATE
e: [kapt] An exception occurred: java.lang.NoClassDefFoundError: io/vertx/lang/rxjava/AbstractRxGenerator
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at io.vertx.lang.reactivex.RxJava2GeneratorLoader.loadGenerators(RxJava2GeneratorLoader.java:12)
	at io.vertx.codegen.CodeGenProcessor.lambda$getCodeGenerators$2(CodeGenProcessor.java:109)
	at java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:267)
	at java.util.Iterator.forEachRemaining(Iterator.java:116)
	at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
	at java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:742)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
	at io.vertx.codegen.CodeGenProcessor.getCodeGenerators(CodeGenProcessor.java:127)
	at io.vertx.codegen.CodeGenProcessor.process(CodeGenProcessor.java:137)
	at org.jetbrains.kotlin.kapt3.base.ProcessorWrapper.process(annotationProcessing.kt:99)
	at com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:794)
	at com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:705)
	at com.sun.tools.javac.processing.JavacProcessingEnvironment.access$1800(JavacProcessingEnvironment.java:91)
	at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1035)
	at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1176)
	at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1170)
	at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1068)
	at org.jetbrains.kotlin.kapt3.base.AnnotationProcessingKt.doAnnotationProcessing(annotationProcessing.kt:55)
	at org.jetbrains.kotlin.kapt3.base.AnnotationProcessingKt.doAnnotationProcessing$default(annotationProcessing.kt:27)
	at org.jetbrains.kotlin.kapt3.AbstractKapt3Extension.runAnnotationProcessing(Kapt3Extension.kt:213)
	at org.jetbrains.kotlin.kapt3.AbstractKapt3Extension.analysisCompleted(Kapt3Extension.kt:178)
	at org.jetbrains.kotlin.kapt3.ClasspathBasedKapt3Extension.analysisCompleted(Kapt3Extension.kt:96)
	at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM$analyzeFilesWithJavaIntegration$2.invoke(TopDownAnalyzerFacadeForJVM.kt:95)
	at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration(TopDownAnalyzerFacadeForJVM.kt:105)
	at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration$default(TopDownAnalyzerFacadeForJVM.kt:82)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler$analyze$1.invoke(KotlinToJVMBytecodeCompiler.kt:375)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler$analyze$1.invoke(KotlinToJVMBytecodeCompiler.kt:67)
	at org.jetbrains.kotlin.cli.common.messages.AnalyzerWithCompilerReport.analyzeAndReport(AnalyzerWithCompilerReport.kt:107)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.analyze(KotlinToJVMBytecodeCompiler.kt:366)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli(KotlinToJVMBytecodeCompiler.kt:120)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:161)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:57)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:96)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:52)
	at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:93)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$1$1$2.invoke(CompileServiceImpl.kt:441)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$1$1$2.invoke(CompileServiceImpl.kt:101)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:1020)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:101)
	at org.jetbrains.kotlin.daemon.common.DummyProfiler.withMeasure(PerfUtils.kt:137)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.checkedCompile(CompileServiceImpl.kt:1062)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.doCompile(CompileServiceImpl.kt:1019)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:440)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
	at sun.rmi.transport.Transport$1.run(Transport.java:200)
	at sun.rmi.transport.Transport$1.run(Transport.java:197)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
	at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:834)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: io.vertx.lang.rxjava.AbstractRxGenerator
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 75 more

> Task :kaptKotlin FAILED

This looks like a bug, can you please create an issue at http://kotl.in/issue and attach a sample project (can be done privately) so we can reproduce the problem? Thank you.