ClassNotFoundException: kotlinx.coroutines.debug.AgentPremain error for 2025.3+ versions

antonkashnikov · March 29, 2026, 3:34pm

Hi, I’m running into an issue with runIde on newer IntelliJ versions.

When I try to run my plugin with IntelliJ IDEA 2026.1, the IDE fails to start and crashes with:

com.intellij.util.lang.UrlClassLoader.findClass(UrlClassLoader.java:267)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:557)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:490)
FATAL ERROR in native method: processing of -javaagent failed, processJavaStart failed
	at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:490)
	at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:558)
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
*** java.lang.instrument ASSERTION FAILED ***: "!errorOutstanding" with message Outstanding error when calling method in invokeJavaAgentMainMethod at s\src\java.instrument\share\native\libinstrument\JPLISAgent.c line: 627
*** java.lang.instrument ASSERTION FAILED ***: "success" with message invokeJavaAgentMainMethod failed at s\src\java.instrument\share\native\libinstrument\JPLISAgent.c line: 466
*** java.lang.instrument ASSERTION FAILED ***: "result" with message agent load/premain call failed at s\src\java.instrument\share\native\libinstrument\JPLISAgent.c line: 429

I face this issue only for IDEA versions 2025.3+. For older versions, everything works fine.
Disable “Attach coroutine agent” in the host IDE hack doesn’t work for me.
The plugin version: id(“org.jetbrains.intellij.platform”) version “2.13.1”

Any chance you can help me to resolve it?

yuriy.artamonov · March 30, 2026, 9:05am

Could you share full logs? We cannot reproduce it with a fresh plugin project on our side

antonkashnikov · March 30, 2026, 12:08pm

@yuriy.artamonov Here are the full logs. We have a multimodule project. Most probebly thats why you can’t reproduce the issue:

6:23:19 PM: Executing ‘runIde’…

Configure project :
{engine.guide=https://javarush.com/groups/posts/2055-razdel-igrih-na-javarush-chastjh-2-opisanie-igrovogo-dvizhka?post=full#Ограничения%20игрового%20движка, plugin_id=com.hitechrush.javarush, product=javarush, project.name=javarush-project, product_title=JavaRush, subscriptions.link=https://javarush.com/prices/my, plugin.id=com.hitechrush.javarush, product.title=JavaRush, default=${default}, sdk.name=Javarush SDK, host=javarush.com, project.root=javarush, project.rider.name=javarush-rider-project}

Configure project :plugin-main
{engine.guide=https://javarush.com/groups/posts/2055-razdel-igrih-na-javarush-chastjh-2-opisanie-igrovogo-dvizhka?post=full#Ограничения%20игрового%20движка, plugin_id=com.hitechrush.javarush, product=javarush, project.name=javarush-project, product_title=JavaRush, subscriptions.link=https://javarush.com/prices/my, plugin.id=com.hitechrush.javarush, product.title=JavaRush, default=${default}, sdk.name=Javarush SDK, host=javarush.com, project.root=javarush, project.rider.name=javarush-rider-project}
[org.jetbrains.intellij.platform] Using Rider as a target IntelliJ Platform with useInstaller = true is currently not supported, please set useInstaller = false instead. See: 

Following 1 plugins could not be created: plugins\fullLine\lib\modules\intellij.fullLine.yaml.jar

Task :initializeIntellijPlatformPlugin
Task :patchPluginXml NO-SOURCE
Task :generateManifest UP-TO-DATE
Task :c-sharp-plugin-service:initializeIntellijPlatformPlugin
Task :c-sharp-plugin-service:generateManifest UP-TO-DATE
Task :common:initializeIntellijPlatformPlugin
Task :common:generateManifest UP-TO-DATE
Task :common:compileJava UP-TO-DATE
Task :common:patchPluginXml NO-SOURCE
Task :common:processResources NO-SOURCE
Task :common:classes UP-TO-DATE
Task :common:instrumentCode UP-TO-DATE
Task :common:jar UP-TO-DATE
Task :common:instrumentedJar UP-TO-DATE
Task :common:composedJar UP-TO-DATE
Task :c-sharp-plugin-service:compileJava UP-TO-DATE
Task :c-sharp-plugin-service:patchPluginXml NO-SOURCE
Task :c-sharp-plugin-service:processResources NO-SOURCE
Task :c-sharp-plugin-service:classes UP-TO-DATE
Task :c-sharp-plugin-service:instrumentCode UP-TO-DATE
Task :c-sharp-plugin-service:jar UP-TO-DATE
Task :c-sharp-plugin-service:instrumentedJar UP-TO-DATE
Task :c-sharp-plugin-service:composedJar UP-TO-DATE
Task :cpp-plugin-services:initializeIntellijPlatformPlugin
Task :cpp-plugin-services:generateManifest UP-TO-DATE
Task :cpp-plugin-services:compileJava UP-TO-DATE
Task :cpp-plugin-services:patchPluginXml NO-SOURCE
Task :cpp-plugin-services:processResources NO-SOURCE
Task :cpp-plugin-services:classes UP-TO-DATE
Task :cpp-plugin-services:instrumentCode UP-TO-DATE
Task :cpp-plugin-services:jar UP-TO-DATE
Task :cpp-plugin-services:instrumentedJar UP-TO-DATE
Task :cpp-plugin-services:composedJar UP-TO-DATE
Task :java-plugin-services:initializeIntellijPlatformPlugin
Task :java-plugin-services:generateManifest UP-TO-DATE
Task :java-plugin-services:compileJava
Task :java-plugin-services:patchPluginXml NO-SOURCE
Task :java-plugin-services:processResources NO-SOURCE
Task :java-plugin-services:classes
Task :java-plugin-services:instrumentCode
Task :java-plugin-services:jar
Task :java-plugin-services:instrumentedJar
Task :java-plugin-services:composedJar
Task :plugin-main:initializeIntellijPlatformPlugin
Task :plugin-main:generateManifest
Task :python-plugin-services:initializeIntellijPlatformPlugin
Task :python-plugin-services:generateManifest
Task :python-plugin-services:compileJava
Task :python-plugin-services:patchPluginXml NO-SOURCE
Task :python-plugin-services:processResources NO-SOURCE
Task :python-plugin-services:classes
Task :python-plugin-services:instrumentCode
Task :python-plugin-services:jar
Task :python-plugin-services:instrumentedJar
Task :python-plugin-services:composedJar
Task :plugin-main:compileJava
Task :plugin-main:patchPluginXml
Task :plugin-main:processResources UP-TO-DATE
Task :plugin-main:classes
Task :plugin-main:instrumentCode
Task :plugin-main:jar
Task :plugin-main:instrumentedJar
Task :plugin-main:composedJar
Task :web-plugin-services:initializeIntellijPlatformPlugin
Task :web-plugin-services:generateManifest
Task :web-plugin-services:compileJava
Task :web-plugin-services:patchPluginXml NO-SOURCE
Task :web-plugin-services:processResources NO-SOURCE
Task :web-plugin-services:classes
Task :web-plugin-services:instrumentCode
Task :web-plugin-services:jar
Task :web-plugin-services:instrumentedJar
Task :web-plugin-services:composedJar
Task :compileJava NO-SOURCE
Task :processResources UP-TO-DATE
Task :classes UP-TO-DATE
Task :instrumentCode UP-TO-DATE
Task :jar UP-TO-DATE
Task :instrumentedJar UP-TO-DATE
Task :composedJar UP-TO-DATE
Task :prepareSandbox

Task :runIde FAILED
[0.011s][warning][cds] Archived non-system classes are disabled because the java.system.class.loader property is specified (value = “com.intellij.util.lang.PathClassLoader”). To use archived non-system classes, this property must not be set
FATAL ERROR in native method: processing of -javaagent failed, processJavaStart failed
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [jvm.dll+0x7c0b19]  (no source info available)
V  [jvm.dll+0x78a2ed]  (no source info available)
V  [jvm.dll+0x49cd2f]  (no source info available)
V  [jvm.dll+0x4fee8a]  (no source info available)
C  [instrument.dll+0x27d8]  (no source info available)
V  [jvm.dll+0x662572]  (no source info available)
V  [jvm.dll+0x9b87bd]  (no source info available)
V  [jvm.dll+0x508951]  (no source info available)
V  [jvm.dll+0x50a2c1]  (no source info available)
C  [jli.dll+0x541a]  (no source info available)
C  [ucrtbase.dll+0x37b0]  (no source info available)
C  [KERNEL32.DLL+0x2e8d7]  (no source info available)
C  [ntdll.dll+0x8c48c]  (no source info available)

60 actionable tasks: 34 executed, 26 up-to-date
Exception in thread “main” java.lang.ClassNotFoundException: kotlinx.coroutines.debug.AgentPremain
at com.intellij.util.lang.UrlClassLoader.findClass(UrlClassLoader.java:267)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:557)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:490)
at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:490)
at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:558)
*** java.lang.instrument ASSERTION FAILED ***: “!errorOutstanding” with message Outstanding error when calling method in invokeJavaAgentMainMethod at s\src\java.instrument\share\native\libinstrument\JPLISAgent.c line: 627
*** java.lang.instrument ASSERTION FAILED ***: “success” with message invokeJavaAgentMainMethod failed at s\src\java.instrument\share\native\libinstrument\JPLISAgent.c line: 466
*** java.lang.instrument ASSERTION FAILED ***: “result” with message agent load/premain call failed at s\src\java.instrument\share\native\libinstrument\JPLISAgent.c line: 429

FAILURE: Build failed with an exception.

What went wrong:
Execution failed for task ‘:runIde’.

Process ‘command ‘C:\Users\akash.gradle\caches\9.0.0\transforms\43c8bf9c0c301d3dffd5795be6c2f88a\transformed\idea-2026.1-win\jbr\bin\java.exe’’ finished with non-zero exit value 1

Try:

Run with --stacktrace option to get the stack trace.
Run with --info or --debug option to get more log output.
Run with --scan to generate a Build Scan (Powered by Develocity).
Get more help at https://help.gradle.org.

BUILD FAILED in 2m 9s
6:25:29 PM: Execution finished ‘runIde’.

robert.novotny · March 31, 2026, 11:41am

I encountered this on my private 3rd party project.

This was a pure Java project, but I had kotlin("jvm") declared.
When I gradle clean-ed and removed .intellijPlatform directory and rebuilt the whole project, the issue disappeared.

antonkashnikov · March 31, 2026, 1:04pm

Thank you, @robert.novotny . Looks like solution

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ClassNotFoundException: kotlinx.coroutines.debug.AgentPremain error for 2025.3+ versions

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