--- old/src/java.base/share/classes/java/util/HashMap.java	2018-12-17 07:25:13.770953982 +0100
+++ new/src/java.base/share/classes/java/util/HashMap.java	2018-12-17 07:25:13.331952967 +0100
@@ -501,9 +501,14 @@
                          (int)ft : MAXIMUM_CAPACITY);
                 if (t > threshold)
                     threshold = tableSizeFor(t);
+            } else {
+                // Because of linked-list buckets constraints, we cannot
+                // expand all at once, but can reduce total resize
+                // effort by repeated doubling now vs later
+                while (table.length <  MAXIMUM_CAPACITY && s > threshold) {
+                    resize();
+                }
             }
-            else if (s > threshold)
-                resize();
             for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
                 K key = e.getKey();
                 V value = e.getValue();