--- jsr166/src/test/tck/MapTest.java	2017/08/23 05:33:00	1.1
+++ jsr166/src/test/tck/MapTest.java	2019/04/24 17:29:50	1.5
@@ -102,7 +102,7 @@ public class MapTest extends JSR166TestC
         final Object v2 = (permitsNullValues && rnd.nextBoolean() && v1 != null)
             ? null : impl.makeValue(2);
 
-        /** If true, always lands in first bucket in hash tables. */
+        // If true, always lands in first bucket in hash tables.
         final boolean poorHash = rnd.nextBoolean();
         class Key implements Comparable<Key> {
             final int i;
@@ -139,6 +139,66 @@ public class MapTest extends JSR166TestC
         assertEquals(1, m.size());
     }
 
+    /**
+     * "Missing" test found while investigating JDK-8210280.
+     * ant -Djsr166.tckTestClass=HashMapTest -Djsr166.methodFilter=testBug8210280 -Djsr166.runsPerTest=1000000 tck
+     */
+    public void testBug8210280() {
+        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
+        final int size1 = rnd.nextInt(32);
+        final int size2 = rnd.nextInt(128);
+
+        final Map m1 = impl.emptyMap();
+        for (int i = 0; i < size1; i++) {
+            int elt = rnd.nextInt(1024 * i, 1024 * (i + 1));
+            assertNull(m1.put(impl.makeKey(elt), impl.makeValue(elt)));
+        }
+
+        final Map m2 = impl.emptyMap();
+        for (int i = 0; i < size2; i++) {
+            int elt = rnd.nextInt(Integer.MIN_VALUE + 1024 * i,
+                                  Integer.MIN_VALUE + 1024 * (i + 1));
+            assertNull(m2.put(impl.makeKey(elt), impl.makeValue(-elt)));
+        }
+
+        final Map m1Copy = impl.emptyMap();
+        m1Copy.putAll(m1);
+
+        m1.putAll(m2);
+
+        for (Object elt : m2.keySet())
+            assertEquals(m2.get(elt), m1.get(elt));
+        for (Object elt : m1Copy.keySet())
+            assertSame(m1Copy.get(elt), m1.get(elt));
+        assertEquals(size1 + size2, m1.size());
+    }
+
+    /**
+     * 8222930: ConcurrentSkipListMap.clone() shares size variable between original and clone
+     */
+    public void testClone() {
+        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
+        final int size = rnd.nextInt(4);
+        final Map map = impl.emptyMap();
+        for (int i = size; i--> 0; )
+            map.put(impl.makeKey(i), impl.makeValue(i));
+        final Map clone = cloneableClone(map);
+        if (clone == null) return;      // not cloneable?
+
+        assertEquals(size, map.size());
+        assertEquals(size, clone.size());
+        assertEquals(map.isEmpty(), clone.isEmpty());
+
+        clone.put(impl.makeKey(-1), impl.makeValue(-1));
+        assertEquals(size, map.size());
+        assertEquals(size + 1, clone.size());
+
+        clone.clear();
+        assertEquals(size, map.size());
+        assertEquals(0, clone.size());
+        assertTrue(clone.isEmpty());
+    }
+
 //     public void testFailsIntentionallyForDebugging() {
 //         fail(impl.klazz().getSimpleName());
 //     }