Stub function for Azure Load Testing - error loading Version 0.1.2 on startup - Netty Error filtering class

[danzone]

Hi all, I've installed Stub function for Azure Load Testing plugin, with following info:

• Stub function for Azure Load Testing plugin: 0.1.2
• Apache JMeter: 5.6.3
• O.S. Windows 11
• JVM: OpenJDK 64-Bit Server 21.0.8

When JMeter starts, following errors appears in the console:

2025-10-28 17:21:29,314 INFO o.a.j.r.ClassFinder: Will scan jar C:\Users\e001362\AppData\Roaming\apache-jmeter-5.6.3\lib\ext\jmeter-plugins-azure-load-testing-stub-0.1.2.jar with filter ExtendsClassFilter [parents=[interface org.apache.jmeter.gui.action.Command], inner=false, contains=null, notContains=null]. Consider exposing JMeter plugins via META-INF/services, and add JMeter-Skip-Class-Scanning=true manifest attribute so JMeter can skip classfile scanning
2025-10-28 17:21:31,096 ERROR o.a.j.r.ClassFinder: Error filtering class io.netty.util.internal.shaded.org.jctools.queues.atomic.unpadded.MpscAtomicUnpaddedArrayQueue, it will be ignored
java.lang.IllegalAccessError: class io.netty.util.internal.shaded.org.jctools.queues.atomic.unpadded.MpscAtomicUnpaddedArrayQueueL1Pad cannot access its abstract superclass io.netty.util.internal.shaded.org.jctools.queues.atomic.AtomicReferenceArrayQueue (io.netty.util.internal.shaded.org.jctools.queues.atomic.unpadded.MpscAtomicUnpaddedArrayQueueL1Pad and io.netty.util.internal.shaded.org.jctools.queues.atomic.AtomicReferenceArrayQueue are in unnamed module of loader org.apache.jmeter.DynamicClassLoader @3b07d329)
	at java.base/java.lang.ClassLoader.defineClass1(Native Method) ~[?:?]
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1027) ~[?:?]
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150) ~[?:?]
	at java.base/java.net.URLClassLoader.defineClass(URLClassLoader.java:524) ~[?:?]
	at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:427) ~[?:?]
	at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:421) ~[?:?]
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:714) ~[?:?]
	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:420) ~[?:?]
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:593) ~[?:?]
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526) ~[?:?]
	at java.base/java.lang.ClassLoader.defineClass1(Native Method) ~[?:?]
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1027) ~[?:?]
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150) ~[?:?]
	at java.base/java.net.URLClassLoader.defineClass(URLClassLoader.java:524) ~[?:?]
	at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:427) ~[?:?]
	at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:421) ~[?:?]
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:714) ~[?:?]
	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:420) ~[?:?]
...
	at org.apache.jmeter.gui.action.ActionRouter.populateCommandMap(ActionRouter.java:318) [ApacheJMeter_core.jar:5.6.3]
	at org.apache.jmeter.JMeterGuiLauncher$startGuiInternal$2.invokeSuspend(JMeterGuiLauncher.kt:105) [ApacheJMeter_core.jar:5.6.3]
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) [kotlin-stdlib-1.9.22.jar:1.9.22-release-704]
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:108) [kotlinx-coroutines-core-jvm-1.7.3.jar:?]
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:584) [kotlinx-coroutines-core-jvm-1.7.3.jar:?]
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:793) [kotlinx-coroutines-core-jvm-1.7.3.jar:?]
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:697) [kotlinx-coroutines-core-jvm-1.7.3.jar:?]
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:684) [kotlinx-coroutines-core-jvm-1.7.3.jar:?]
2025-10-28 17:21:31,122 ERROR o.a.j.r.ClassFinder: Error filtering class io.netty.util.internal.shaded.org.jctools.queues.atomic.unpadded.MpscAtomicUnpaddedArrayQueueConsumerIndexField, it will be ignored
java.lang.IllegalAccessError: class io.netty.util.internal.shaded.org.jctools.queues.atomic.unpadded.MpscAtomicUnpaddedArrayQueueL1Pad cannot access its abstract superclass io.netty.util.internal.shaded.org.jctools.queues.atomic.AtomicReferenceArrayQueue (io.netty.util.internal.shaded.org.jctools.queues.atomic.unpadded.MpscAtomicUnpaddedArrayQueueL1Pad and io.netty.util.internal.shaded.org.jctools.queues.atomic.AtomicReferenceArrayQueue are in unnamed module of loader org.apache.jmeter.DynamicClassLoader @3b07d329)
	at java.base/java.lang.ClassLoader.defineClass1(Native Method) ~[?:?]
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1027) ~[?:?]

The same happens with version 0.1.1, while version 0.1.0 works but it seems to have other issues (see #37 ).

Thanks in advance.

Daniele

[kuniteru]

Hi @danzone ,

I performed a reproduction test and encountered no issues in my environment.

• Stub function for Azure Load Testing plugin: 0.1.2
• Apache JMeter: 5.6.3
• O.S. Windows 11
• JVM: OpenJDK 64-Bit Server VM Microsoft-11933218 (build 21.0.8+9-LTS, mixed mode, sharing)

Are you loading other plugins into JMeter as well?
If so, try loading only the jmeter-plugins-azure-load-testing-stub-0.1.2.jar and excluding all others. Does the same error occur?

If that doesn't produce the error, the next step would be to try loading all other plugins except jmeter-plugins-azure-load-testing-stub-0.1.2.jar. How does that work?

It seems highly likely that multiple plugins are using conflicting libraries, which makes troubleshooting difficult...

Thanks,