Currently the agent is built with ASM 8.0.1, This version is around 2 years old at this point and only supports up to Java 14, It would be nice to upgrade this so the agent can be used on newer JDK versions, as attempting to instrument for example a JDK17 VM leads to an IllegalArgumentException:

Oct 27, 2022 2:05:14 PM org.openjdk.jmc.agent.Transformer doJFRLogging
SEVERE: Failed to instrument length()I
java.lang.IllegalArgumentException: Unsupported class file major version 61
at org.openjdk.jmc.internal.org.objectweb.asm.ClassReader.<init>(ClassReader.java:196)
at org.openjdk.jmc.internal.org.objectweb.asm.ClassReader.<init>(ClassReader.java:177)
at org.openjdk.jmc.internal.org.objectweb.asm.ClassReader.<init>(ClassReader.java:163)
at org.openjdk.jmc.agent.Transformer.doJFRLogging(Transformer.java:103)
at org.openjdk.jmc.agent.Transformer.doTransform(Transformer.java:85)
at org.openjdk.jmc.agent.Transformer.doTransforms(Transformer.java:75)
at org.openjdk.jmc.agent.Transformer.transform(Transformer.java:63)
at java.instrument/java.lang.instrument.ClassFileTransformer.transform(ClassFileTransformer.java:244)
at java.instrument/sun.instrument.TransformerManager.transform(TransformerManager.java:188)
at java.instrument/sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:541)
at java.instrument/sun.instrument.InstrumentationImpl.retransformClasses0(Native Method)
at java.instrument/sun.instrument.InstrumentationImpl.retransformClasses(InstrumentationImpl.java:169)
at org.openjdk.jmc.agent.jmx.AgentController.defineEventProbes(AgentController.java:80)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:72)
at jdk.internal.reflect.GeneratedMethodAccessor27.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at java.base/sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:262)
at java.management/com.sun.jmx.mbeanserver.ConvertingMethod.invokeWithOpenReturn(ConvertingMethod.java:193)
at java.management/com.sun.jmx.mbeanserver.ConvertingMethod.invokeWithOpenReturn(ConvertingMethod.java:175)
at java.management/com.sun.jmx.mbeanserver.MXBeanIntrospector.invokeM2(MXBeanIntrospector.java:117)
at java.management/com.sun.jmx.mbeanserver.MXBeanIntrospector.invokeM2(MXBeanIntrospector.java:54)
at java.management/com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:237)
at java.management/com.sun.jmx.mbeanserver.PerInterface.invoke(PerInterface.java:138)
at java.management/com.sun.jmx.mbeanserver.MBeanSupport.invoke(MBeanSupport.java:252)
at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:814)
at java.management/com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:802)
at org.openjdk.jmc.rjmx.internal.MCMBeanServerConnection.invoke(MCMBeanServerConnection.java:258)
at org.openjdk.jmc.console.agent.AgentJmxHelper.defineEventProbes(AgentJmxHelper.java:140)
at org.openjdk.jmc.console.agent.editor.AgentEditorUi.applyConfig(AgentEditorUi.java:308)
at org.openjdk.jmc.console.agent.editor.AgentEditorUi.loadPreset(AgentEditorUi.java:167)
at org.openjdk.jmc.console.agent.editor.AgentEditorAction.run(AgentEditorAction.java:57)
at org.eclipse.jface.action.Action.runWithEvent(Action.java:474)
at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:580)
at org.eclipse.jface.action.ActionContributionItem.lambda$5(ActionContributionItem.java:453)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5884)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1522)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:5126)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4576)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1041)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:644)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:551)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:156)
at org.openjdk.jmc.rcp.application.Application.start(Application.java:64)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:136)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:401)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:659)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:596)
at org.eclipse.equinox.launcher.Main.run(Main.java:1467)
at org.eclipse.equinox.launcher.Main.main(Main.java:1440)

Version 9.4 which supports up to JDK20 was released earlier this month and seems good to update to.