--- old/src/hotspot/share/gc/shared/referenceProcessor.cpp	2018-05-14 18:03:03.576099339 -0400
+++ new/src/hotspot/share/gc/shared/referenceProcessor.cpp	2018-05-14 18:03:03.332086584 -0400
@@ -379,7 +379,8 @@
     iter.load_ptrs(DEBUG_ONLY(!discovery_is_atomic() /* allow_null_referent */));
     if (iter.referent() == NULL) {
       // Reference has been cleared since discovery; only possible if
-      // discovery is not atomic.  Remove reference from list.
+      // discovery is not atomic (checked by load_ptrs).  Remove
+      // reference from list.
       log_dropped_ref(iter, "cleared");
       iter.remove();
       iter.move_to_next();
--- old/src/java.base/share/classes/java/lang/ref/Reference.java	2018-05-14 18:03:04.372140957 -0400
+++ new/src/java.base/share/classes/java/lang/ref/Reference.java	2018-05-14 18:03:04.088126108 -0400
@@ -76,21 +76,23 @@
      * queue = ReferenceQueue.NULL.
      *
      * The collector only needs to examine the referent field and the
-     * discovered field to determine whether a normal Reference object needs
-     * special treatment.  If the referent is non-null and not known to be
-     * live, then it may need to be discovered for possible later
-     * notification.  But if the discovered field is non-null, then either (1)
-     * it has already been discovered, or (2) it is in the pending list.
+     * discovered field to determine whether a normal (non-FinalReference)
+     * Reference object needs special treatment.  If the referent is non-null
+     * and not known to be live, then it may need to be discovered for
+     * possible later notification.  But if the discovered field is non-null,
+     * then either (1) it has already been discovered, or (2) it is in the
+     * pending list.
      *
-     * FinalReference differs from other references, because a FinalReference
-     * is not cleared when notified.  The referent being null or not cannot be
-     * used to distinguish between the active state and pending or inactive
-     * states.  However, FinalReferences do not support enqueue().  Instead,
-     * the next field of a FinalReference object is set to the object when it
-     * is added to the pending list, and the use of this as the value of next
-     * in the enqueued and dequeued states maintains the non-active state.  An
-     * additional check that the next field is null is required to determine
-     * that a FinalReference object is active.
+     * FinalReference (which exists to support finalization, which was
+     * deprecated in JDK 9) differs from normal references, because a
+     * FinalReference is not cleared when notified.  The referent being null
+     * or not cannot be used to distinguish between the active state and
+     * pending or inactive states.  However, FinalReferences do not support
+     * enqueue().  Instead, the next field of a FinalReference object is set
+     * to "this" when it is added to the pending list.  The use of "this"
+     * as the value of next in the enqueued and dequeued states maintains the
+     * non-active state.  An additional check that the next field is null is
+     * required to determine that a FinalReference object is active.
      *
      * Initial states:
      *   active/registered