--- jsr166/src/test/tck/ConcurrentHashMapTest.java	2016/07/17 03:40:07	1.48
+++ jsr166/src/test/tck/ConcurrentHashMapTest.java	2017/01/04 06:09:58	1.52
@@ -16,6 +16,8 @@ import java.util.Map;
 import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 
 import junit.framework.Test;
 import junit.framework.TestSuite;
@@ -32,7 +34,7 @@ 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");
@@ -331,6 +333,21 @@ 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 +825,9 @@ 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 +836,5 @@ public class ConcurrentHashMapTest exten
             assertFalse(keySet.removeAll(removeMe));
         assertEquals(mapSize, map.size());
     }
+
 }