--- a/src/java.base/share/classes/java/util/TreeSet.java	Tue Aug 27 22:26:42 2019 +0200
+++ b/src/java.base/share/classes/java/util/TreeSet.java	Tue Aug 27 14:44:21 2019 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -302,9 +302,7 @@
             m instanceof TreeMap) {
             SortedSet<? extends E> set = (SortedSet<? extends E>) c;
             TreeMap<E,Object> map = (TreeMap<E, Object>) m;
-            Comparator<?> cc = set.comparator();
-            Comparator<? super E> mc = map.comparator();
-            if (cc==mc || (cc != null && cc.equals(mc))) {
+            if (Objects.equals(set.comparator(), map.comparator())) {
                 map.addAllForTreeSet(set, PRESENT);
                 return true;
             }