src/java.base/share/classes/java/util/HashMap.java

@@ -499,13 +499,18 @@
                 float ft = ((float)s / loadFactor) + 1.0F;
                 int t = ((ft < (float)MAXIMUM_CAPACITY) ?
                          (int)ft : MAXIMUM_CAPACITY);
                 if (t > threshold)
                     threshold = tableSizeFor(t);
-            }
-            else if (s > threshold)
+            } 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();
+                }
+            }
             for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
                 K key = e.getKey();
                 V value = e.getValue();
                 putVal(hash(key), key, value, false, evict);
             }