--- jsr166/src/test/tck/ConcurrentHashMapTest.java	2016/07/17 03:40:07	1.48
+++ jsr166/src/test/tck/ConcurrentHashMapTest.java	2017/03/18 20:42:20	1.54
@@ -32,7 +32,7 @@ public class ConcurrentHashMapTest exten
      * Returns a new map from Integers 1-5 to Strings "A"-"E".
      */
     private static ConcurrentHashMap<Integer, String> map5() {
-        ConcurrentHashMap map = new ConcurrentHashMap<Integer, String>(5);
+        ConcurrentHashMap<Integer, String> map = new ConcurrentHashMap<>(5);
         assertTrue(map.isEmpty());
         map.put(one, "A");
         map.put(two, "B");
@@ -119,7 +119,7 @@ public class ConcurrentHashMapTest exten
         ConcurrentHashMap<BI, Boolean> m =
             new ConcurrentHashMap<BI, Boolean>();
         for (int i = 0; i < size; i++) {
-            assertTrue(m.put(new CI(i), true) == null);
+            assertNull(m.put(new CI(i), true));
         }
         for (int i = 0; i < size; i++) {
             assertTrue(m.containsKey(new CI(i)));
@@ -140,7 +140,7 @@ public class ConcurrentHashMapTest exten
             BS bs = new BS(String.valueOf(i));
             LexicographicList<BI> bis = new LexicographicList<BI>(bi);
             LexicographicList<BS> bss = new LexicographicList<BS>(bs);
-            assertTrue(m.putIfAbsent(bis, true) == null);
+            assertNull(m.putIfAbsent(bis, true));
             assertTrue(m.containsKey(bis));
             if (m.putIfAbsent(bss, true) == null)
                 assertTrue(m.containsKey(bss));
@@ -331,6 +331,21 @@ public class ConcurrentHashMapTest exten
     }
 
     /**
+     * Test keySet().removeAll on empty map
+     */
+    public void testKeySet_empty_removeAll() {
+        ConcurrentHashMap<Integer, String> map = new ConcurrentHashMap<>();
+        Set<Integer> set = map.keySet();
+        set.removeAll(Collections.emptyList());
+        assertTrue(map.isEmpty());
+        assertTrue(set.isEmpty());
+        // following is test for JDK-8163353
+        set.removeAll(Collections.emptySet());
+        assertTrue(map.isEmpty());
+        assertTrue(set.isEmpty());
+    }
+
+    /**
      * keySet.toArray returns contains all keys
      */
     public void testKeySetToArray() {
@@ -808,9 +823,9 @@ public class ConcurrentHashMapTest exten
      * ant -Djsr166.tckTestClass=ConcurrentHashMapTest -Djsr166.methodFilter=testRemoveAll_performance -Djsr166.expensiveTests=true tck
      */
     public void testRemoveAll_performance() {
-        int mapSize = expensiveTests ? 1_000_000 : 100;
-        int iterations = expensiveTests ? 500 : 2;
-        ConcurrentHashMap<Integer, Integer> map = new ConcurrentHashMap<>();
+        final int mapSize = expensiveTests ? 1_000_000 : 100;
+        final int iterations = expensiveTests ? 500 : 2;
+        final ConcurrentHashMap<Integer, Integer> map = new ConcurrentHashMap<>();
         for (int i = 0; i < mapSize; i++)
             map.put(i, i);
         Set<Integer> keySet = map.keySet();
@@ -819,4 +834,5 @@ public class ConcurrentHashMapTest exten
             assertFalse(keySet.removeAll(removeMe));
         assertEquals(mapSize, map.size());
     }
+
 }