This happens when we are trying to read the property from the private annotation:

java.lang.IllegalAccessException: class org.openjdk.jol.vm.ContendedSupport cannot access interface jdk.internal.vm.annotation.Contended (in module java.base) because module java.base does not export jdk.internal.vm.annotation to unnamed module @22635ba0
at jdk.internal.reflect.Reflection.throwIllegalAccessException(java.base@9-ea/Reflection.java:405)
at jdk.internal.reflect.Reflection.throwIllegalAccessException(java.base@9-ea/Reflection.java:396)
at jdk.internal.reflect.Reflection.ensureMemberAccess(java.base@9-ea/Reflection.java:98)
at java.lang.reflect.AccessibleObject.slowCheckMemberAccess(java.base@9-ea/AccessibleObject.java:355)
at java.lang.reflect.AccessibleObject.checkAccess(java.base@9-ea/AccessibleObject.java:347)
at java.lang.reflect.Method.invoke(java.base@9-ea/Method.java:529)
at org.openjdk.jol.vm.ContendedSupport.pullValue(ContendedSupport.java:96)
at org.openjdk.jol.vm.ContendedSupport.contendedGroup(ContendedSupport.java:74)
at org.openjdk.jol.info.FieldData.parse(FieldData.java:66)
at org.openjdk.jol.info.ClassData.parse(ClassData.java:109)
at org.openjdk.jol.info.ClassData.parseClass(ClassData.java:62)
at org.openjdk.jol.info.ClassData.addSuperClassData(ClassData.java:188)
at org.openjdk.jol.info.ClassData.parse(ClassData.java:103)
at org.openjdk.jol.info.ClassData.parseClass(ClassData.java:62)
at org.openjdk.jol.info.ClassLayout.parseClass(ClassLayout.java:68)
at org.openjdk.jol.info.ClassLayout.parseClass(ClassLayout.java:52)
at org.openjdk.jol.samples.JOLSample_09_Contended.main(JOLSample_09_Contended.java:55)