--- a/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java	Tue Jan 16 18:24:32 2018 -0800
+++ b/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java	Tue Jan 16 18:28:39 2018 -0800
@@ -717,12 +717,12 @@
      */
     static Class<?> comparableClassFor(Object x) {
         if (x instanceof Comparable) {
-            Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
+            Class<?> c; Type[] ts, as; ParameterizedType p;
             if ((c = x.getClass()) == String.class) // bypass checks
                 return c;
             if ((ts = c.getGenericInterfaces()) != null) {
-                for (int i = 0; i < ts.length; ++i) {
-                    if (((t = ts[i]) instanceof ParameterizedType) &&
+                for (Type t : ts) {
+                    if ((t instanceof ParameterizedType) &&
                         ((p = (ParameterizedType)t).getRawType() ==
                          Comparable.class) &&
                         (as = p.getActualTypeArguments()) != null &&
@@ -2328,15 +2328,15 @@
      * @param check if <0, don't check resize, if <= 1 only check if uncontended
      */
     private final void addCount(long x, int check) {
-        CounterCell[] as; long b, s;
-        if ((as = counterCells) != null ||
+        CounterCell[] cs; long b, s;
+        if ((cs = counterCells) != null ||
             !U.compareAndSetLong(this, BASECOUNT, b = baseCount, s = b + x)) {
-            CounterCell a; long v; int m;
+            CounterCell c; long v; int m;
             boolean uncontended = true;
-            if (as == null || (m = as.length - 1) < 0 ||
-                (a = as[ThreadLocalRandom.getProbe() & m]) == null ||
+            if (cs == null || (m = cs.length - 1) < 0 ||
+                (c = cs[ThreadLocalRandom.getProbe() & m]) == null ||
                 !(uncontended =
-                  U.compareAndSetLong(a, CELLVALUE, v = a.value, v + x))) {
+                  U.compareAndSetLong(c, CELLVALUE, v = c.value, v + x))) {
                 fullAddCount(x, uncontended);
                 return;
             }
@@ -2574,13 +2574,12 @@
     }
 
     final long sumCount() {
-        CounterCell[] as = counterCells; CounterCell a;
+        CounterCell[] cs = counterCells;
         long sum = baseCount;
-        if (as != null) {
-            for (int i = 0; i < as.length; ++i) {
-                if ((a = as[i]) != null)
-                    sum += a.value;
-            }
+        if (cs != null) {
+            for (CounterCell c : cs)
+                if (c != null)
+                    sum += c.value;
         }
         return sum;
     }
@@ -2595,9 +2594,9 @@
         }
         boolean collide = false;                // True if last slot nonempty
         for (;;) {
-            CounterCell[] as; CounterCell a; int n; long v;
-            if ((as = counterCells) != null && (n = as.length) > 0) {
-                if ((a = as[(n - 1) & h]) == null) {
+            CounterCell[] cs; CounterCell c; int n; long v;
+            if ((cs = counterCells) != null && (n = cs.length) > 0) {
+                if ((c = cs[(n - 1) & h]) == null) {
                     if (cellsBusy == 0) {            // Try to attach new Cell
                         CounterCell r = new CounterCell(x); // Optimistic create
                         if (cellsBusy == 0 &&
@@ -2623,21 +2622,17 @@
                 }
                 else if (!wasUncontended)       // CAS already known to fail
                     wasUncontended = true;      // Continue after rehash
-                else if (U.compareAndSetLong(a, CELLVALUE, v = a.value, v + x))
+                else if (U.compareAndSetLong(c, CELLVALUE, v = c.value, v + x))
                     break;
-                else if (counterCells != as || n >= NCPU)
+                else if (counterCells != cs || n >= NCPU)
                     collide = false;            // At max size or stale
                 else if (!collide)
                     collide = true;
                 else if (cellsBusy == 0 &&
                          U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
                     try {
-                        if (counterCells == as) {// Expand table unless stale
-                            CounterCell[] rs = new CounterCell[n << 1];
-                            for (int i = 0; i < n; ++i)
-                                rs[i] = as[i];
-                            counterCells = rs;
-                        }
+                        if (counterCells == cs) // Expand table unless stale
+                            counterCells = Arrays.copyOf(cs, n << 1);
                     } finally {
                         cellsBusy = 0;
                     }
@@ -2646,11 +2641,11 @@
                 }
                 h = ThreadLocalRandom.advanceProbe(h);
             }
-            else if (cellsBusy == 0 && counterCells == as &&
+            else if (cellsBusy == 0 && counterCells == cs &&
                      U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
                 boolean init = false;
                 try {                           // Initialize table
-                    if (counterCells == as) {
+                    if (counterCells == cs) {
                         CounterCell[] rs = new CounterCell[2];
                         rs[h & 1] = new CounterCell(x);
                         counterCells = rs;