Kapt is not working properly with OpenJDK 16

Question

I have an application that uses Kotlin 1.5.0 and Kapt for mapstructs. I have updated my JDK to 16 and I get the following compilation error:

Failed to execute goal org.jetbrains.kotlin:kotlin-maven-plugin:1.5.0:kapt (kapt) on project X: Compilation failure
java.lang.IllegalAccessError: class org.jetbrains.kotlin.kapt3.base.KaptContext (in unnamed module @0x248e24b) cannot access class com.sun.tools.javac.util.Context (in module jdk.compiler) because module jdk.compiler does not export com.sun.tools.javac.util to unnamed module @0x248e24b
    at org.jetbrains.kotlin.kapt3.base.KaptContext.<init>(KaptContext.kt:29)
    at org.jetbrains.kotlin.kapt3.KaptContextForStubGeneration.<init>(KaptContextForStubGeneration.kt:40)
    at org.jetbrains.kotlin.kapt3.AbstractKapt3Extension.contextForStubGeneration(Kapt3Extension.kt:285)
    at org.jetbrains.kotlin.kapt3.AbstractKapt3Extension.analysisCompleted(Kapt3Extension.kt:169)
    at org.jetbrains.kotlin.kapt3.ClasspathBasedKapt3Extension.analysisCompleted(Kapt3Extension.kt:100)
    at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration$invokeExtensionsOnAnalysisComplete(TopDownAnalyzerFacadeForJVM.kt:111)
    at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration(TopDownAnalyzerFacadeForJVM.kt:121)
    at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration$default(TopDownAnalyzerFacadeForJVM.kt:85)
    at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler$analyze$1.invoke(KotlinToJVMBytecodeCompiler.kt:514)
    at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler$analyze$1.invoke(KotlinToJVMBytecodeCompiler.kt:505)
    at org.jetbrains.kotlin.cli.common.messages.AnalyzerWithCompilerReport.analyzeAndReport(AnalyzerWithCompilerReport.kt:112)
    at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.analyze(KotlinToJVMBytecodeCompiler.kt:505)
    at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli(KotlinToJVMBytecodeCompiler.kt:189)
    at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli$default(KotlinToJVMBytecodeCompiler.kt:155)
    at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:169)
    at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:52)
    at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:88)
    at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:44)
    at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:98)
    at org.jetbrains.kotlin.maven.KotlinCompileMojoBase.execCompiler(KotlinCompileMojoBase.java:228)
    at org.jetbrains.kotlin.maven.K2JVMCompileMojo.execCompiler(K2JVMCompileMojo.java:237)
    at org.jetbrains.kotlin.maven.kapt.KaptJVMCompilerMojo.execCompiler(KaptJVMCompilerMojo.java:152)
    at org.jetbrains.kotlin.maven.kapt.KaptJVMCompilerMojo.execCompiler(KaptJVMCompilerMojo.java:44)
    at org.jetbrains.kotlin.maven.KotlinCompileMojoBase.execute(KotlinCompileMojoBase.java:209)
    at org.jetbrains.kotlin.maven.K2JVMCompileMojo.execute(K2JVMCompileMojo.java:222)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:957)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:193)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:567)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:347)
    at org.codehaus.classworlds.Launcher.main(Launcher.java:47)

I have seen that there is an open issue with Kapt and JDK 16: https://youtrack.jetbrains.com/issue/KT-45545, I'm trying to use --add-opens as args options in the kotlin-maven-plugin but seems they are not working properly:

<plugin>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-maven-plugin</artifactId>
            <executions>
                <execution>
                    <id>kapt</id>
                    <goals>
                        <goal>kapt</goal>
                    </goals>
                    <configuration>
                        <sourceDirs>
                            <sourceDir>src/main/kotlin</sourceDir>
                            <sourceDir>src/main/java</sourceDir>
                        </sourceDirs>
                        <annotationProcessorPaths>
                            <annotationProcessorPath>
                                <groupId>org.mapstruct</groupId>
                                <artifactId>mapstruct-processor</artifactId>
                                <version>${mapstruct.version}</version>
                            </annotationProcessorPath>
                        </annotationProcessorPaths>
                    </configuration>
                </execution>
            </executions>
            <configuration>
                <args>
                    <arg>-Xjsr305=strict</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED</arg>
                    <arg>-X--add-opens=jdk.compiler/com.sun.tools.javac.jvm=ALL-UNNAMED</arg>
                </args>
                <compilerPlugins>
                    <plugin>spring</plugin>
                </compilerPlugins>
            </configuration>
            <dependencies>
                <dependency>
                    <groupId>org.jetbrains.kotlin</groupId>
                    <artifactId>kotlin-maven-allopen</artifactId>
                    <version>${kotlin.version}</version>
                </dependency>
            </dependencies>
</plugin>

when I execute again maven with this args options tells me the following:

[INFO] --- kotlin-maven-plugin:1.5.0:kapt (kapt) @ X ---
[WARNING] Source root doesn't exist: /home/nico/IdeaProjects/X/X/src/main/java
[WARNING] 'tools.jar' was not found, kapt may work unreliably
[INFO] Applied plugin: 'spring'
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
[WARNING] Flag is not supported by this version of the compiler: -X--add-opens=jdk.compiler/com.sun.tools.javac.jvm=ALL-UNNAMED

• How can I add these options to kotlin-maven-plugin?
• Is there any other posibility to run Kapt with JDK 16 and maven?

Answer 1

According to JetBrains comment:

Add org.gradle.jvmargs=--illegal-access=permit to gradle.properties

Options can be combined by separating them with a space:

org.gradle.jvmargs=-Xmx1536m --illegal-access=permit

Answer 2

How can I add these options to kotlin-maven-plugin?

Unfortunely, you can't. kotlin-maven-plugin does not accept JVM arguments.

Is there any other posibility to run Kapt with JDK 16 and maven?

What helped me was creating a .mvn/jvm.config file in my project with the following content:

 --illegal-access=permit --add-opens jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.jvm=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED

It works correct when I build the project in command line but keep in mind it might not work when you use IDE tools to manage Maven build, for example IntelliJ completely ignores the file.

Answer 3

Now I still not found solution for JDK 16

But I can work arround by using JDK 15, you can download at: https://www.oracle.com/java/technologies/javase/jdk15-archive-downloads.html