Exception in thread "main" com.sun.tools.attach.AttachOperationFailedException: java.lang.IllegalArgumentException: Unknown diagnostic command
at jdk.attach/sun.tools.attach.VirtualMachineImpl.execute(VirtualMachineImpl.java:130)
at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.executeCommand(HotSpotVirtualMachine.java:309)
at jdk.jcmd/sun.tools.jmap.JMap.executeCommandForPid(JMap.java:133)
at jdk.jcmd/sun.tools.jmap.JMap.main(JMap.java:118)

Line 117-118 of JMap.java are:

            } else if (option.equals("-clstats")) {
                executeCommandForPid(pid, "jcmd", "GC.class_stats");

GC.class_stats was removed by JDK-8232759