Error during attachment ByteBuddyAgent while Mocking java static method using Mockk

Question

I am working on a gradle project, trying to unit test while mocking a java static method using Mockk.My unit test is simply just trying to mock a static class. Trying to do some research there was some word that it's a ByteBuddyAgent issue, but i'm not sure if the issue is the same and if there's any fix. Thanks in advance.

class UtilsTest {
 @Before
    fun setup() {
        mockkStatic(UtilKotlin::class)
    }

    @Test
    fun invFirstReturnsItem() {
        Assert.assertTrue(true)
    }
}

And I am getting the error:

java.lang.ExceptionInInitializerError
    at tribot.utils.UtilsTest.setup(UtilsTest.kt:28)
    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 org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
    at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:118)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
    at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:412)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalStateException: Error during attachment using: net.bytebuddy.agent.ByteBuddyAgent$AttachmentProvider$Compound@399c2f7f
    at net.bytebuddy.agent.ByteBuddyAgent.install(ByteBuddyAgent.java:613)
    at net.bytebuddy.agent.ByteBuddyAgent.install(ByteBuddyAgent.java:586)
    at net.bytebuddy.agent.ByteBuddyAgent.install(ByteBuddyAgent.java:538)
    at net.bytebuddy.agent.ByteBuddyAgent.install(ByteBuddyAgent.java:515)
    at io.mockk.proxy.jvm.JvmMockKAgentFactory.initInstrumentation(JvmMockKAgentFactory.kt:134)
    at io.mockk.proxy.jvm.JvmMockKAgentFactory.init(JvmMockKAgentFactory.kt:34)
    at io.mockk.impl.JvmMockKGateway.<init>(JvmMockKGateway.kt:46)
    at io.mockk.impl.JvmMockKGateway.<clinit>(JvmMockKGateway.kt:172)
    ... 48 more
Caused by: java.lang.reflect.InvocationTargetException
    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 net.bytebuddy.agent.Attacher.install(Attacher.java:106)
    at net.bytebuddy.agent.ByteBuddyAgent.install(ByteBuddyAgent.java:608)
    ... 55 more
Caused by: com.sun.tools.attach.AttachNotSupportedException: no providers installed
    at com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:55)
    ... 61 more

Here is my build.gradle file

plugins {
   id 'java'
   id 'org.jetbrains.kotlin.jvm' version '1.3.72'
}

group 'org.example'
version '1.0-SNAPSHOT'


repositories {
    mavenCentral()
    mavenLocal()
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    testImplementation group: 'junit', name: 'junit', version: '4.12'
    testImplementation "io.mockk:mockk:1.10.0"
}

compileKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

compileTestKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

Answer 1

The reason is at the bottom of the stack: com.sun.tools.attach.AttachNotSupportedException: no providers installed

It seems like you are not using a full JDK to run your tests what is typically the cause for this problem since JREs are shipped without some of the tooling binaries. What Java installation are you using?

Answer 2

Turns out my IDE was a bit corrupted. It also came with it's own pre-packaged version of OpenJDK which i believe is the culprit. I re-installed my IDE and it works fine.