The JVMTI spec has a typo ("bot" => "not"):
JVMTI_HEAP_REFERENCE_SUPERCLASS :
Reference from a class to its superclass. A callback is bot sent if the superclass is java.lang.Object. Note: loaded classes define superclasses via a constant pool reference, so the referenced superclass may also be reported with a JVMTI_HEAP_REFERENCE_CONSTANT_POOL reference kind.

See the link:
  http://docs.oracle.com/javase/8/docs/platform/jvmti/jvmti.html#jvmtiHeapReferenceKind