--- a/src/share/classes/com/sun/jndi/toolkit/ctx/Continuation.java	Thu May 23 09:48:44 2013 -0300
+++ b/src/share/classes/com/sun/jndi/toolkit/ctx/Continuation.java	Wed May 29 13:22:58 2013 -0300
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -90,14 +90,16 @@
      * Constructs a new instance of Continuation.
      * @param top The name of the object that is to be resolved/operated upon.
      *          This becomes the Continuation's 'starter' and is used to
-     *          calculate the "resolved name" when filling  in a NamingException.
+     *          calculate the "resolved name" when filling in a NamingException.
      * @param environment The environment used by the caller. It is used
-     * when setting the "environment" of a CannotProceedException.
+     *          when setting the "environment" of a CannotProceedException.
      */
+    @SuppressWarnings("unchecked")  // For Hashtable clone: environment.clone()
     public Continuation(Name top, Hashtable<?,?> environment) {
         super();
         starter = top;
-        this.environment = environment;
+        this.environment = (Hashtable<?,?>)
+                ((environment == null) ? null : environment.clone());
     }
 
     /**

--- a/src/share/classes/com/sun/jndi/toolkit/dir/LazySearchEnumerationImpl.java	Thu May 23 09:48:44 2013 -0300
+++ b/src/share/classes/com/sun/jndi/toolkit/dir/LazySearchEnumerationImpl.java	Wed May 29 13:22:58 2013 -0300
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -69,6 +69,7 @@
             }
     }
 
+    @SuppressWarnings("unchecked")      // For Hashtable clone: env.clone()
     public LazySearchEnumerationImpl(NamingEnumeration<Binding> candidates,
         AttrFilter filter, SearchControls cons,
         Context ctx, Hashtable<String, Object> env, boolean useFactory)
@@ -76,7 +77,8 @@
 
             this.candidates = candidates;
             this.filter = filter;
-            this.env = env;
+            this.env = (Hashtable<String, Object>)
+                    ((env == null) ? null : env.clone());
             this.context = ctx;
             this.useFactory = useFactory;
 

--- a/src/share/classes/com/sun/jndi/toolkit/url/GenericURLContext.java	Thu May 23 09:48:44 2013 -0300
+++ b/src/share/classes/com/sun/jndi/toolkit/url/GenericURLContext.java	Wed May 29 13:22:58 2013 -0300
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -53,7 +53,8 @@
     @SuppressWarnings("unchecked") // Expect Hashtable<String, Object>
     public GenericURLContext(Hashtable<?,?> env) {
         // context that is not tied to any specific URL
-        myEnv = (Hashtable<String, Object>)env;  // copied on write
+        myEnv =
+            (Hashtable<String, Object>)(env == null ? null : env.clone());
     }
 
     public void close() throws NamingException {
@@ -488,22 +489,19 @@
         return result;
     }
 
-    @SuppressWarnings("unchecked") // clone()
     public Object removeFromEnvironment(String propName)
         throws NamingException {
             if (myEnv == null) {
                 return null;
             }
-            myEnv = (Hashtable<String, Object>)myEnv.clone();
             return myEnv.remove(propName);
     }
 
-    @SuppressWarnings("unchecked") // clone()
     public Object addToEnvironment(String propName, Object propVal)
         throws NamingException {
-            myEnv = (myEnv == null)
-                    ? new Hashtable<String, Object>(11, 0.75f)
-                    : (Hashtable<String, Object>)myEnv.clone();
+            if (myEnv == null) {
+                myEnv = new Hashtable<String, Object>(11, 0.75f);
+            }
             return myEnv.put(propName, propVal);
     }
 

--- a/src/share/classes/java/lang/ref/Reference.java	Thu May 23 09:48:44 2013 -0300
+++ b/src/share/classes/java/lang/ref/Reference.java	Wed May 29 13:22:58 2013 -0300
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -138,8 +138,23 @@
                         pending = r.discovered;
                         r.discovered = null;
                     } else {
+                        // The waiting on the lock may cause an OOME because it may try to allocate
+                        // exception objects, so also catch OOME here to avoid silent exit of the
+                        // reference handler thread.
+                        //
+                        // Explicitly define the order of the two exceptions we catch here
+                        // when waiting for the lock.
+                        //
+                        // We do not want to try to potentially load the InterruptedException class
+                        // (which would be done if this was its first use, and InterruptedException
+                        // were checked first) in this situation.
+                        //
+                        // This may lead to the VM not ever trying to load the InterruptedException
+                        // class again.
                         try {
-                            lock.wait();
+                            try {
+                                lock.wait();
+                            } catch (OutOfMemoryError x) { }
                         } catch (InterruptedException x) { }
                         continue;
                     }

--- a/src/share/classes/java/nio/charset/Charset-X-Coder.java.template	Thu May 23 09:48:44 2013 -0300
+++ b/src/share/classes/java/nio/charset/Charset-X-Coder.java.template	Wed May 29 13:22:58 2013 -0300
@@ -34,6 +34,7 @@
 import java.nio.BufferUnderflowException;
 import java.lang.ref.WeakReference;
 import java.nio.charset.CoderMalfunctionError;                  // javadoc
+import java.util.Arrays;
 
 
 /**
@@ -244,7 +245,12 @@
      *          which is never <tt>null</tt> and is never empty
      */
     public final $replType$ replacement() {
+#if[decoder]
         return replacement;
+#end[decoder]
+#if[encoder]
+        return Arrays.copyOf(replacement, replacement.$replLength$);
+#end[encoder]
     }
 
     /**
@@ -280,12 +286,15 @@
             throw new IllegalArgumentException("Empty replacement");
         if (len > max$ItypesPerOtype$)
             throw new IllegalArgumentException("Replacement too long");
+#if[decoder]
+        this.replacement = newReplacement;
+#end[decoder]
 #if[encoder]
         if (!isLegalReplacement(newReplacement))
             throw new IllegalArgumentException("Illegal replacement");
+        this.replacement = Arrays.copyOf(newReplacement, newReplacement.$replLength$);
 #end[encoder]
-        this.replacement = newReplacement;
-        implReplaceWith(newReplacement);
+        implReplaceWith(this.replacement);
         return this;
     }
 

--- a/src/share/classes/java/nio/file/Files.java	Thu May 23 09:48:44 2013 -0300
+++ b/src/share/classes/java/nio/file/Files.java	Wed May 29 13:22:58 2013 -0300
@@ -25,9 +25,11 @@
 
 package java.nio.file;
 
+import java.nio.ByteBuffer;
 import java.nio.file.attribute.*;
 import java.nio.file.spi.FileSystemProvider;
 import java.nio.file.spi.FileTypeDetector;
+import java.nio.channels.FileChannel;
 import java.nio.channels.SeekableByteChannel;
 import java.io.Closeable;
 import java.io.InputStream;
@@ -2945,40 +2947,6 @@
     }
 
     /**
-     * Read all the bytes from an input stream. The {@code initialSize}
-     * parameter indicates the initial size of the byte[] to allocate.
-     */
-    private static byte[] read(InputStream source, int initialSize)
-        throws IOException
-    {
-        int capacity = initialSize;
-        byte[] buf = new byte[capacity];
-        int nread = 0;
-        int rem = buf.length;
-        int n;
-        // read to EOF which may read more or less than initialSize (eg: file
-        // is truncated while we are reading)
-        while ((n = source.read(buf, nread, rem)) > 0) {
-            nread += n;
-            rem -= n;
-            assert rem >= 0;
-            if (rem == 0) {
-                // need larger buffer
-                int newCapacity = capacity << 1;
-                if (newCapacity < 0) {
-                    if (capacity == Integer.MAX_VALUE)
-                        throw new OutOfMemoryError("Required array size too large");
-                    newCapacity = Integer.MAX_VALUE;
-                }
-                rem = newCapacity - capacity;
-                buf = Arrays.copyOf(buf, newCapacity);
-                capacity = newCapacity;
-            }
-        }
-        return (capacity == nread) ? buf : Arrays.copyOf(buf, nread);
-    }
-
-    /**
      * Read all the bytes from a file. The method ensures that the file is
      * closed when all bytes have been read or an I/O error, or other runtime
      * exception, is thrown.
@@ -3003,12 +2971,22 @@
      *          method is invoked to check read access to the file.
      */
     public static byte[] readAllBytes(Path path) throws IOException {
-        long size = size(path);
-        if (size > (long)Integer.MAX_VALUE)
-            throw new OutOfMemoryError("Required array size too large");
+        try (FileChannel fc = FileChannel.open(path)) {
+            long size = fc.size();
+            if (size > (long)Integer.MAX_VALUE)
+                throw new OutOfMemoryError("Required array size too large");
 
-        try (InputStream in = newInputStream(path)) {
-             return read(in, (int)size);
+            byte[] arr = new byte[(int)size];
+            ByteBuffer bb = ByteBuffer.wrap(arr);
+            while (bb.hasRemaining()) {
+                if (fc.read(bb) < 0) {
+                    // truncated
+                    break;
+                }
+            }
+
+            int nread = bb.position();
+            return (nread == size) ? arr : Arrays.copyOf(arr, nread);
         }
     }
 

--- a/src/share/classes/java/util/Arrays.java	Thu May 23 09:48:44 2013 -0300
+++ b/src/share/classes/java/util/Arrays.java	Wed May 29 13:22:58 2013 -0300
@@ -40,7 +40,6 @@
 import java.util.stream.LongStream;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
-import static java.util.ArraysParallelSortHelpers.*;
 
 /**
  * This class contains various methods for manipulating arrays (such as
@@ -70,17 +69,62 @@
 public class Arrays {
 
     /**
-     * The minimum array length below which the sorting algorithm will not
-     * further partition the sorting task.
+     * The minimum array length below which a parallel sorting
+     * algorithm will not further partition the sorting task. Using
+     * smaller sizes typically results in memory contention across
+     * tasks that makes parallel speedups unlikely.
      */
-    // reasonable default so that we don't overcreate tasks
-    private static final int MIN_ARRAY_SORT_GRAN = 256;
+    private static final int MIN_ARRAY_SORT_GRAN = 1 << 13;
 
     // Suppresses default constructor, ensuring non-instantiability.
     private Arrays() {}
 
+    /**
+     * A comparator that implements the natural ordering of a group of
+     * mutually comparable elements. May be used when a supplied
+     * comparator is null. To simplify code-sharing within underlying
+     * implementations, the compare method only declares type Object
+     * for its second argument.
+     *
+     * Arrays class implementor's note: It is an empirical matter
+     * whether ComparableTimSort offers any performance benefit over
+     * TimSort used with this comparator.  If not, you are better off
+     * deleting or bypassing ComparableTimSort.  There is currently no
+     * empirical case for separating them for parallel sorting, so all
+     * public Object parallelSort methods use the same comparator
+     * based implementation.
+     */
+    static final class NaturalOrder implements Comparator<Object> {
+        @SuppressWarnings("unchecked")
+        public int compare(Object first, Object second) {
+            return ((Comparable<Object>)first).compareTo(second);
+        }
+        static final NaturalOrder INSTANCE = new NaturalOrder();
+    }
+
+    /**
+     * Checks that {@code fromIndex} and {@code toIndex} are in
+     * the range and throws an exception if they aren't.
+     */
+    private static void rangeCheck(int arrayLength, int fromIndex, int toIndex) {
+        if (fromIndex > toIndex) {
+            throw new IllegalArgumentException(
+                    "fromIndex(" + fromIndex + ") > toIndex(" + toIndex + ")");
+        }
+        if (fromIndex < 0) {
+            throw new ArrayIndexOutOfBoundsException(fromIndex);
+        }
+        if (toIndex > arrayLength) {
+            throw new ArrayIndexOutOfBoundsException(toIndex);
+        }
+    }
+
     /*
-     * Sorting of primitive type arrays.
+     * Sorting methods. Note that all public "sort" methods take the
+     * same form: Performing argument checks if necessary, and then
+     * expanding arguments into those required for the internal
+     * implementation methods residing in other package-private
+     * classes (except for legacyMergeSort, included in this class).
      */
 
     /**
@@ -95,7 +139,7 @@
      * @param a the array to be sorted
      */
     public static void sort(int[] a) {
-        DualPivotQuicksort.sort(a);
+        DualPivotQuicksort.sort(a, 0, a.length - 1, null, 0, 0);
     }
 
     /**
@@ -120,7 +164,7 @@
      */
     public static void sort(int[] a, int fromIndex, int toIndex) {
         rangeCheck(a.length, fromIndex, toIndex);
-        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1);
+        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
     }
 
     /**
@@ -135,7 +179,7 @@
      * @param a the array to be sorted
      */
     public static void sort(long[] a) {
-        DualPivotQuicksort.sort(a);
+        DualPivotQuicksort.sort(a, 0, a.length - 1, null, 0, 0);
     }
 
     /**
@@ -160,7 +204,7 @@
      */
     public static void sort(long[] a, int fromIndex, int toIndex) {
         rangeCheck(a.length, fromIndex, toIndex);
-        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1);
+        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
     }
 
     /**
@@ -175,7 +219,7 @@
      * @param a the array to be sorted
      */
     public static void sort(short[] a) {
-        DualPivotQuicksort.sort(a);
+        DualPivotQuicksort.sort(a, 0, a.length - 1, null, 0, 0);
     }
 
     /**
@@ -200,7 +244,7 @@
      */
     public static void sort(short[] a, int fromIndex, int toIndex) {
         rangeCheck(a.length, fromIndex, toIndex);
-        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1);
+        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
     }
 
     /**
@@ -215,7 +259,7 @@
      * @param a the array to be sorted
      */
     public static void sort(char[] a) {
-        DualPivotQuicksort.sort(a);
+        DualPivotQuicksort.sort(a, 0, a.length - 1, null, 0, 0);
     }
 
     /**
@@ -240,7 +284,7 @@
      */
     public static void sort(char[] a, int fromIndex, int toIndex) {
         rangeCheck(a.length, fromIndex, toIndex);
-        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1);
+        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
     }
 
     /**
@@ -255,7 +299,7 @@
      * @param a the array to be sorted
      */
     public static void sort(byte[] a) {
-        DualPivotQuicksort.sort(a);
+        DualPivotQuicksort.sort(a, 0, a.length - 1);
     }
 
     /**
@@ -303,7 +347,7 @@
      * @param a the array to be sorted
      */
     public static void sort(float[] a) {
-        DualPivotQuicksort.sort(a);
+        DualPivotQuicksort.sort(a, 0, a.length - 1, null, 0, 0);
     }
 
     /**
@@ -336,7 +380,7 @@
      */
     public static void sort(float[] a, int fromIndex, int toIndex) {
         rangeCheck(a.length, fromIndex, toIndex);
-        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1);
+        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
     }
 
     /**
@@ -359,7 +403,7 @@
      * @param a the array to be sorted
      */
     public static void sort(double[] a) {
-        DualPivotQuicksort.sort(a);
+        DualPivotQuicksort.sort(a, 0, a.length - 1, null, 0, 0);
     }
 
     /**
@@ -392,7 +436,742 @@
      */
     public static void sort(double[] a, int fromIndex, int toIndex) {
         rangeCheck(a.length, fromIndex, toIndex);
-        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1);
+        DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
+    }
+
+    /**
+     * Sorts the specified array into ascending numerical order.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(byte[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(byte[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(byte[] a) {
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, 0, n - 1);
+        else
+            new ArraysParallelSortHelpers.FJByte.Sorter
+                (null, a, new byte[n], 0, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the array into ascending numerical order.
+     * The range to be sorted extends from the index {@code fromIndex},
+     * inclusive, to the index {@code toIndex}, exclusive. If
+     * {@code fromIndex == toIndex}, the range to be sorted is empty.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(byte[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(byte[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element, inclusive, to be sorted
+     * @param toIndex the index of the last element, exclusive, to be sorted
+     *
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+     * @throws ArrayIndexOutOfBoundsException
+     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(byte[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, fromIndex, toIndex - 1);
+        else
+            new ArraysParallelSortHelpers.FJByte.Sorter
+                (null, a, new byte[n], fromIndex, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified array into ascending numerical order.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(char[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(char[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(char[] a) {
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, 0, n - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJChar.Sorter
+                (null, a, new char[n], 0, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the array into ascending numerical order.
+     * The range to be sorted extends from the index {@code fromIndex},
+     * inclusive, to the index {@code toIndex}, exclusive. If
+     * {@code fromIndex == toIndex}, the range to be sorted is empty.
+     *
+      @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(char[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(char[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element, inclusive, to be sorted
+     * @param toIndex the index of the last element, exclusive, to be sorted
+     *
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+     * @throws ArrayIndexOutOfBoundsException
+     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(char[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJChar.Sorter
+                (null, a, new char[n], fromIndex, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified array into ascending numerical order.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(short[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(short[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(short[] a) {
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, 0, n - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJShort.Sorter
+                (null, a, new short[n], 0, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the array into ascending numerical order.
+     * The range to be sorted extends from the index {@code fromIndex},
+     * inclusive, to the index {@code toIndex}, exclusive. If
+     * {@code fromIndex == toIndex}, the range to be sorted is empty.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(short[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(short[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element, inclusive, to be sorted
+     * @param toIndex the index of the last element, exclusive, to be sorted
+     *
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+     * @throws ArrayIndexOutOfBoundsException
+     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(short[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJShort.Sorter
+                (null, a, new short[n], fromIndex, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified array into ascending numerical order.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(int[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(int[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(int[] a) {
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, 0, n - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJInt.Sorter
+                (null, a, new int[n], 0, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the array into ascending numerical order.
+     * The range to be sorted extends from the index {@code fromIndex},
+     * inclusive, to the index {@code toIndex}, exclusive. If
+     * {@code fromIndex == toIndex}, the range to be sorted is empty.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(int[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(int[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element, inclusive, to be sorted
+     * @param toIndex the index of the last element, exclusive, to be sorted
+     *
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+     * @throws ArrayIndexOutOfBoundsException
+     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(int[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJInt.Sorter
+                (null, a, new int[n], fromIndex, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified array into ascending numerical order.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(long[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(long[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(long[] a) {
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, 0, n - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJLong.Sorter
+                (null, a, new long[n], 0, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the array into ascending numerical order.
+     * The range to be sorted extends from the index {@code fromIndex},
+     * inclusive, to the index {@code toIndex}, exclusive. If
+     * {@code fromIndex == toIndex}, the range to be sorted is empty.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(long[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(long[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element, inclusive, to be sorted
+     * @param toIndex the index of the last element, exclusive, to be sorted
+     *
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+     * @throws ArrayIndexOutOfBoundsException
+     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(long[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJLong.Sorter
+                (null, a, new long[n], fromIndex, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified array into ascending numerical order.
+     *
+     * <p>The {@code <} relation does not provide a total order on all float
+     * values: {@code -0.0f == 0.0f} is {@code true} and a {@code Float.NaN}
+     * value compares neither less than, greater than, nor equal to any value,
+     * even itself. This method uses the total order imposed by the method
+     * {@link Float#compareTo}: {@code -0.0f} is treated as less than value
+     * {@code 0.0f} and {@code Float.NaN} is considered greater than any
+     * other value and all {@code Float.NaN} values are considered equal.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(float[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(float[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(float[] a) {
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, 0, n - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJFloat.Sorter
+                (null, a, new float[n], 0, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the array into ascending numerical order.
+     * The range to be sorted extends from the index {@code fromIndex},
+     * inclusive, to the index {@code toIndex}, exclusive. If
+     * {@code fromIndex == toIndex}, the range to be sorted is empty.
+     *
+     * <p>The {@code <} relation does not provide a total order on all float
+     * values: {@code -0.0f == 0.0f} is {@code true} and a {@code Float.NaN}
+     * value compares neither less than, greater than, nor equal to any value,
+     * even itself. This method uses the total order imposed by the method
+     * {@link Float#compareTo}: {@code -0.0f} is treated as less than value
+     * {@code 0.0f} and {@code Float.NaN} is considered greater than any
+     * other value and all {@code Float.NaN} values are considered equal.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(float[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(float[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element, inclusive, to be sorted
+     * @param toIndex the index of the last element, exclusive, to be sorted
+     *
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+     * @throws ArrayIndexOutOfBoundsException
+     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(float[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJFloat.Sorter
+                (null, a, new float[n], fromIndex, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified array into ascending numerical order.
+     *
+     * <p>The {@code <} relation does not provide a total order on all double
+     * values: {@code -0.0d == 0.0d} is {@code true} and a {@code Double.NaN}
+     * value compares neither less than, greater than, nor equal to any value,
+     * even itself. This method uses the total order imposed by the method
+     * {@link Double#compareTo}: {@code -0.0d} is treated as less than value
+     * {@code 0.0d} and {@code Double.NaN} is considered greater than any
+     * other value and all {@code Double.NaN} values are considered equal.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(double[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(double[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(double[] a) {
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, 0, n - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJDouble.Sorter
+                (null, a, new double[n], 0, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the array into ascending numerical order.
+     * The range to be sorted extends from the index {@code fromIndex},
+     * inclusive, to the index {@code toIndex}, exclusive. If
+     * {@code fromIndex == toIndex}, the range to be sorted is empty.
+     *
+     * <p>The {@code <} relation does not provide a total order on all double
+     * values: {@code -0.0d == 0.0d} is {@code true} and a {@code Double.NaN}
+     * value compares neither less than, greater than, nor equal to any value,
+     * even itself. This method uses the total order imposed by the method
+     * {@link Double#compareTo}: {@code -0.0d} is treated as less than value
+     * {@code 0.0d} and {@code Double.NaN} is considered greater than any
+     * other value and all {@code Double.NaN} values are considered equal.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(double[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(double[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element, inclusive, to be sorted
+     * @param toIndex the index of the last element, exclusive, to be sorted
+     *
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
+     * @throws ArrayIndexOutOfBoundsException
+     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
+     *
+     * @since 1.8
+     */
+    public static void parallelSort(double[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            DualPivotQuicksort.sort(a, fromIndex, toIndex - 1, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJDouble.Sorter
+                (null, a, new double[n], fromIndex, n, 0,
+                 ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g).invoke();
+    }
+
+    /**
+     * Sorts the specified array of objects into ascending order, according
+     * to the {@linkplain Comparable natural ordering} of its elements.
+     * All elements in the array must implement the {@link Comparable}
+     * interface.  Furthermore, all elements in the array must be
+     * <i>mutually comparable</i> (that is, {@code e1.compareTo(e2)} must
+     * not throw a {@code ClassCastException} for any elements {@code e1}
+     * and {@code e2} in the array).
+     *
+     * <p>This sort is guaranteed to be <i>stable</i>:  equal elements will
+     * not be reordered as a result of the sort.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(Object[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(Object[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     *
+     * @throws ClassCastException if the array contains elements that are not
+     *         <i>mutually comparable</i> (for example, strings and integers)
+     * @throws IllegalArgumentException (optional) if the natural
+     *         ordering of the array elements is found to violate the
+     *         {@link Comparable} contract
+     *
+     * @since 1.8
+     */
+    @SuppressWarnings("unchecked")
+    public static <T extends Comparable<? super T>> void parallelSort(T[] a) {
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            TimSort.sort(a, 0, n, NaturalOrder.INSTANCE, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJObject.Sorter<T>
+                (null, a,
+                 (T[])Array.newInstance(a.getClass().getComponentType(), n),
+                 0, n, 0, ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g, NaturalOrder.INSTANCE).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the specified array of objects into
+     * ascending order, according to the
+     * {@linkplain Comparable natural ordering} of its
+     * elements.  The range to be sorted extends from index
+     * {@code fromIndex}, inclusive, to index {@code toIndex}, exclusive.
+     * (If {@code fromIndex==toIndex}, the range to be sorted is empty.)  All
+     * elements in this range must implement the {@link Comparable}
+     * interface.  Furthermore, all elements in this range must be <i>mutually
+     * comparable</i> (that is, {@code e1.compareTo(e2)} must not throw a
+     * {@code ClassCastException} for any elements {@code e1} and
+     * {@code e2} in the array).
+     *
+     * <p>This sort is guaranteed to be <i>stable</i>:  equal elements will
+     * not be reordered as a result of the sort.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(Object[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(Object[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element (inclusive) to be
+     *        sorted
+     * @param toIndex the index of the last element (exclusive) to be sorted
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex} or
+     *         (optional) if the natural ordering of the array elements is
+     *         found to violate the {@link Comparable} contract
+     * @throws ArrayIndexOutOfBoundsException if {@code fromIndex < 0} or
+     *         {@code toIndex > a.length}
+     * @throws ClassCastException if the array contains elements that are
+     *         not <i>mutually comparable</i> (for example, strings and
+     *         integers).
+     *
+     * @since 1.8
+     */
+    @SuppressWarnings("unchecked")
+    public static <T extends Comparable<? super T>>
+    void parallelSort(T[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            TimSort.sort(a, fromIndex, toIndex, NaturalOrder.INSTANCE, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJObject.Sorter<T>
+                (null, a,
+                 (T[])Array.newInstance(a.getClass().getComponentType(), n),
+                 fromIndex, n, 0, ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g, NaturalOrder.INSTANCE).invoke();
+    }
+
+    /**
+     * Sorts the specified array of objects according to the order induced by
+     * the specified comparator.  All elements in the array must be
+     * <i>mutually comparable</i> by the specified comparator (that is,
+     * {@code c.compare(e1, e2)} must not throw a {@code ClassCastException}
+     * for any elements {@code e1} and {@code e2} in the array).
+     *
+     * <p>This sort is guaranteed to be <i>stable</i>:  equal elements will
+     * not be reordered as a result of the sort.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(Object[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(Object[]) Arrays.sort} method. The algorithm requires a
+     * working space no greater than the size of the original array. The
+     * {@link ForkJoinPool#commonPool() ForkJoin common pool} is used to
+     * execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param cmp the comparator to determine the order of the array.  A
+     *        {@code null} value indicates that the elements'
+     *        {@linkplain Comparable natural ordering} should be used.
+     * @throws ClassCastException if the array contains elements that are
+     *         not <i>mutually comparable</i> using the specified comparator
+     * @throws IllegalArgumentException (optional) if the comparator is
+     *         found to violate the {@link java.util.Comparator} contract
+     *
+     * @since 1.8
+     */
+    @SuppressWarnings("unchecked")
+    public static <T> void parallelSort(T[] a, Comparator<? super T> cmp) {
+        if (cmp == null)
+            cmp = NaturalOrder.INSTANCE;
+        int n = a.length, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            TimSort.sort(a, 0, n, cmp, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJObject.Sorter<T>
+                (null, a,
+                 (T[])Array.newInstance(a.getClass().getComponentType(), n),
+                 0, n, 0, ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g, cmp).invoke();
+    }
+
+    /**
+     * Sorts the specified range of the specified array of objects according
+     * to the order induced by the specified comparator.  The range to be
+     * sorted extends from index {@code fromIndex}, inclusive, to index
+     * {@code toIndex}, exclusive.  (If {@code fromIndex==toIndex}, the
+     * range to be sorted is empty.)  All elements in the range must be
+     * <i>mutually comparable</i> by the specified comparator (that is,
+     * {@code c.compare(e1, e2)} must not throw a {@code ClassCastException}
+     * for any elements {@code e1} and {@code e2} in the range).
+     *
+     * <p>This sort is guaranteed to be <i>stable</i>:  equal elements will
+     * not be reordered as a result of the sort.
+     *
+     * @implNote The sorting algorithm is a parallel sort-merge that breaks the
+     * array into sub-arrays that are themselves sorted and then merged. When
+     * the sub-array length reaches a minimum granularity, the sub-array is
+     * sorted using the appropriate {@link Arrays#sort(Object[]) Arrays.sort}
+     * method. If the length of the specified array is less than the minimum
+     * granularity, then it is sorted using the appropriate {@link
+     * Arrays#sort(Object[]) Arrays.sort} method. The algorithm requires a working
+     * space no greater than the size of the specified range of the original
+     * array. The {@link ForkJoinPool#commonPool() ForkJoin common pool} is
+     * used to execute any parallel tasks.
+     *
+     * @param a the array to be sorted
+     * @param fromIndex the index of the first element (inclusive) to be
+     *        sorted
+     * @param toIndex the index of the last element (exclusive) to be sorted
+     * @param cmp the comparator to determine the order of the array.  A
+     *        {@code null} value indicates that the elements'
+     *        {@linkplain Comparable natural ordering} should be used.
+     * @throws IllegalArgumentException if {@code fromIndex > toIndex} or
+     *         (optional) if the natural ordering of the array elements is
+     *         found to violate the {@link Comparable} contract
+     * @throws ArrayIndexOutOfBoundsException if {@code fromIndex < 0} or
+     *         {@code toIndex > a.length}
+     * @throws ClassCastException if the array contains elements that are
+     *         not <i>mutually comparable</i> (for example, strings and
+     *         integers).
+     *
+     * @since 1.8
+     */
+    @SuppressWarnings("unchecked")
+    public static <T> void parallelSort(T[] a, int fromIndex, int toIndex,
+                                        Comparator<? super T> cmp) {
+        rangeCheck(a.length, fromIndex, toIndex);
+        if (cmp == null)
+            cmp = NaturalOrder.INSTANCE;
+        int n = toIndex - fromIndex, p, g;
+        if (n <= MIN_ARRAY_SORT_GRAN ||
+            (p = ForkJoinPool.getCommonPoolParallelism()) == 1)
+            TimSort.sort(a, fromIndex, toIndex, cmp, null, 0, 0);
+        else
+            new ArraysParallelSortHelpers.FJObject.Sorter<T>
+                (null, a,
+                 (T[])Array.newInstance(a.getClass().getComponentType(), n),
+                 fromIndex, n, 0, ((g = n / (p << 2)) <= MIN_ARRAY_SORT_GRAN) ?
+                 MIN_ARRAY_SORT_GRAN : g, cmp).invoke();
     }
 
     /*
@@ -412,39 +1191,6 @@
                     "java.util.Arrays.useLegacyMergeSort")).booleanValue();
     }
 
-    /*
-     * If this platform has an optimizing VM, check whether ComparableTimSort
-     * offers any performance benefit over TimSort in conjunction with a
-     * comparator that returns:
-     *    {@code ((Comparable)first).compareTo(Second)}.
-     * If not, you are better off deleting ComparableTimSort to
-     * eliminate the code duplication.  In other words, the commented
-     * out code below is the preferable implementation for sorting
-     * arrays of Comparables if it offers sufficient performance.
-     */
-
-//    /**
-//     * A comparator that implements the natural ordering of a group of
-//     * mutually comparable elements.  Using this comparator saves us
-//     * from duplicating most of the code in this file (one version for
-//     * Comparables, one for explicit Comparators).
-//     */
-//    private static final Comparator<Object> NATURAL_ORDER =
-//            new Comparator<Object>() {
-//        @SuppressWarnings("unchecked")
-//        public int compare(Object first, Object second) {
-//            return ((Comparable<Object>)first).compareTo(second);
-//        }
-//    };
-//
-//    public static void sort(Object[] a) {
-//        sort(a, 0, a.length, NATURAL_ORDER);
-//    }
-//
-//    public static void sort(Object[] a, int fromIndex, int toIndex) {
-//        sort(a, fromIndex, toIndex, NATURAL_ORDER);
-//    }
-
     /**
      * Sorts the specified array of objects into ascending order, according
      * to the {@linkplain Comparable natural ordering} of its elements.
@@ -491,7 +1237,7 @@
         if (LegacyMergeSort.userRequested)
             legacyMergeSort(a);
         else
-            ComparableTimSort.sort(a);
+            ComparableTimSort.sort(a, 0, a.length, null, 0, 0);
     }
 
     /** To be removed in a future release. */
@@ -553,16 +1299,16 @@
      *         integers).
      */
     public static void sort(Object[] a, int fromIndex, int toIndex) {
+        rangeCheck(a.length, fromIndex, toIndex);
         if (LegacyMergeSort.userRequested)
             legacyMergeSort(a, fromIndex, toIndex);
         else
-            ComparableTimSort.sort(a, fromIndex, toIndex);
+            ComparableTimSort.sort(a, fromIndex, toIndex, null, 0, 0);
     }
 
     /** To be removed in a future release. */
     private static void legacyMergeSort(Object[] a,
                                         int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
         Object[] aux = copyOfRange(a, fromIndex, toIndex);
         mergeSort(aux, a, fromIndex, toIndex, -fromIndex);
     }
@@ -676,10 +1422,12 @@
      *         found to violate the {@link Comparator} contract
      */
     public static <T> void sort(T[] a, Comparator<? super T> c) {
+        if (c == null)
+            c = NaturalOrder.INSTANCE;
         if (LegacyMergeSort.userRequested)
             legacyMergeSort(a, c);
         else
-            TimSort.sort(a, c);
+            TimSort.sort(a, 0, a.length, c, null, 0, 0);
     }
 
     /** To be removed in a future release. */
@@ -744,16 +1492,18 @@
      */
     public static <T> void sort(T[] a, int fromIndex, int toIndex,
                                 Comparator<? super T> c) {
+        if (c == null)
+            c = NaturalOrder.INSTANCE;
+        rangeCheck(a.length, fromIndex, toIndex);
         if (LegacyMergeSort.userRequested)
             legacyMergeSort(a, fromIndex, toIndex, c);
         else
-            TimSort.sort(a, fromIndex, toIndex, c);
+            TimSort.sort(a, fromIndex, toIndex, c, null, 0, 0);
     }
 
     /** To be removed in a future release. */
     private static <T> void legacyMergeSort(T[] a, int fromIndex, int toIndex,
                                             Comparator<? super T> c) {
-        rangeCheck(a.length, fromIndex, toIndex);
         T[] aux = copyOfRange(a, fromIndex, toIndex);
         if (c==null)
             mergeSort(aux, a, fromIndex, toIndex, -fromIndex);
@@ -809,630 +1559,6 @@
         }
     }
 
-    /*
-     * Parallel sorting of primitive type arrays.
-     */
-
-    /**
-     * Sorts the specified array into ascending numerical order.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(byte[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(byte[] a) {
-        parallelSort(a, 0, a.length);
-    }
-
-    /**
-     * Sorts the specified range of the array into ascending order. The range
-     * to be sorted extends from the index {@code fromIndex}, inclusive, to
-     * the index {@code toIndex}, exclusive. If {@code fromIndex == toIndex},
-     * the range to be sorted is empty.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(byte[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element, inclusive, to be sorted
-     * @param toIndex the index of the last element, exclusive, to be sorted
-     *
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
-     * @throws ArrayIndexOutOfBoundsException
-     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(byte[] a, int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        int gran = getSplitThreshold(nelements);
-        FJByte.Sorter task = new FJByte.Sorter(a, new byte[a.length], fromIndex,
-                                               nelements, gran);
-        task.invoke();
-    }
-
-    /**
-     * Sorts the specified array into ascending numerical order.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(char[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(char[] a) {
-        parallelSort(a, 0, a.length);
-    }
-
-    /**
-     * Sorts the specified range of the array into ascending order. The range
-     * to be sorted extends from the index {@code fromIndex}, inclusive, to
-     * the index {@code toIndex}, exclusive. If {@code fromIndex == toIndex},
-     * the range to be sorted is empty.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(char[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element, inclusive, to be sorted
-     * @param toIndex the index of the last element, exclusive, to be sorted
-     *
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
-     * @throws ArrayIndexOutOfBoundsException
-     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(char[] a, int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        int gran = getSplitThreshold(nelements);
-        FJChar.Sorter task = new FJChar.Sorter(a, new char[a.length], fromIndex,
-                                               nelements, gran);
-        task.invoke();
-    }
-
-    /**
-     * Sorts the specified array into ascending numerical order.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(short[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(short[] a) {
-        parallelSort(a, 0, a.length);
-    }
-
-    /**
-     * Sorts the specified range of the array into ascending order. The range
-     * to be sorted extends from the index {@code fromIndex}, inclusive, to
-     * the index {@code toIndex}, exclusive. If {@code fromIndex == toIndex},
-     * the range to be sorted is empty.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(short[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element, inclusive, to be sorted
-     * @param toIndex the index of the last element, exclusive, to be sorted
-     *
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
-     * @throws ArrayIndexOutOfBoundsException
-     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(short[] a, int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        int gran = getSplitThreshold(nelements);
-        FJShort.Sorter task = new FJShort.Sorter(a, new short[a.length], fromIndex,
-                                                 nelements, gran);
-        task.invoke();
-    }
-
-    /**
-     * Sorts the specified array into ascending numerical order.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(int[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(int[] a) {
-        parallelSort(a, 0, a.length);
-    }
-
-    /**
-     * Sorts the specified range of the array into ascending order. The range
-     * to be sorted extends from the index {@code fromIndex}, inclusive, to
-     * the index {@code toIndex}, exclusive. If {@code fromIndex == toIndex},
-     * the range to be sorted is empty.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(int[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element, inclusive, to be sorted
-     * @param toIndex the index of the last element, exclusive, to be sorted
-     *
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
-     * @throws ArrayIndexOutOfBoundsException
-     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(int[] a, int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        int gran = getSplitThreshold(nelements);
-        FJInt.Sorter task = new FJInt.Sorter(a, new int[a.length], fromIndex,
-                                             nelements, gran);
-        task.invoke();
-    }
-
-    /**
-     * Sorts the specified array into ascending numerical order.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(long[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(long[] a) {
-        parallelSort(a, 0, a.length);
-    }
-
-    /**
-     * Sorts the specified range of the array into ascending order. The range
-     * to be sorted extends from the index {@code fromIndex}, inclusive, to
-     * the index {@code toIndex}, exclusive. If {@code fromIndex == toIndex},
-     * the range to be sorted is empty.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(long[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element, inclusive, to be sorted
-     * @param toIndex the index of the last element, exclusive, to be sorted
-     *
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
-     * @throws ArrayIndexOutOfBoundsException
-     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(long[] a, int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        int gran = getSplitThreshold(nelements);
-        FJLong.Sorter task = new FJLong.Sorter(a, new long[a.length], fromIndex,
-                                               nelements, gran);
-        task.invoke();
-    }
-
-    /**
-     * Sorts the specified array into ascending numerical order.
-     *
-     * <p>The {@code <} relation does not provide a total order on all float
-     * values: {@code -0.0f == 0.0f} is {@code true} and a {@code Float.NaN}
-     * value compares neither less than, greater than, nor equal to any value,
-     * even itself. This method uses the total order imposed by the method
-     * {@link Float#compareTo}: {@code -0.0f} is treated as less than value
-     * {@code 0.0f} and {@code Float.NaN} is considered greater than any
-     * other value and all {@code Float.NaN} values are considered equal.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(float[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(float[] a) {
-        parallelSort(a, 0, a.length);
-    }
-
-    /**
-     * Sorts the specified range of the array into ascending order. The range
-     * to be sorted extends from the index {@code fromIndex}, inclusive, to
-     * the index {@code toIndex}, exclusive. If {@code fromIndex == toIndex},
-     * the range to be sorted is empty.
-     *
-     * <p>The {@code <} relation does not provide a total order on all float
-     * values: {@code -0.0f == 0.0f} is {@code true} and a {@code Float.NaN}
-     * value compares neither less than, greater than, nor equal to any value,
-     * even itself. This method uses the total order imposed by the method
-     * {@link Float#compareTo}: {@code -0.0f} is treated as less than value
-     * {@code 0.0f} and {@code Float.NaN} is considered greater than any
-     * other value and all {@code Float.NaN} values are considered equal.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(float[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element, inclusive, to be sorted
-     * @param toIndex the index of the last element, exclusive, to be sorted
-     *
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
-     * @throws ArrayIndexOutOfBoundsException
-     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(float[] a, int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        int gran = getSplitThreshold(nelements);
-        FJFloat.Sorter task = new FJFloat.Sorter(a, new float[a.length], fromIndex,
-                                                 nelements, gran);
-        task.invoke();
-    }
-
-    /**
-     * Sorts the specified array into ascending numerical order.
-     *
-     * <p>The {@code <} relation does not provide a total order on all double
-     * values: {@code -0.0d == 0.0d} is {@code true} and a {@code Double.NaN}
-     * value compares neither less than, greater than, nor equal to any value,
-     * even itself. This method uses the total order imposed by the method
-     * {@link Double#compareTo}: {@code -0.0d} is treated as less than value
-     * {@code 0.0d} and {@code Double.NaN} is considered greater than any
-     * other value and all {@code Double.NaN} values are considered equal.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(double[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(double[] a) {
-        parallelSort(a, 0, a.length);
-    }
-
-    /**
-     * Sorts the specified range of the array into ascending order. The range
-     * to be sorted extends from the index {@code fromIndex}, inclusive, to
-     * the index {@code toIndex}, exclusive. If {@code fromIndex == toIndex},
-     * the range to be sorted is empty.
-     *
-     * <p>The {@code <} relation does not provide a total order on all double
-     * values: {@code -0.0d == 0.0d} is {@code true} and a {@code Double.NaN}
-     * value compares neither less than, greater than, nor equal to any value,
-     * even itself. This method uses the total order imposed by the method
-     * {@link Double#compareTo}: {@code -0.0d} is treated as less than value
-     * {@code 0.0d} and {@code Double.NaN} is considered greater than any
-     * other value and all {@code Double.NaN} values are considered equal.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(double[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element, inclusive, to be sorted
-     * @param toIndex the index of the last element, exclusive, to be sorted
-     *
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex}
-     * @throws ArrayIndexOutOfBoundsException
-     *     if {@code fromIndex < 0} or {@code toIndex > a.length}
-     *
-     * @since 1.8
-     */
-    public static void parallelSort(double[] a, int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        int gran = getSplitThreshold(nelements);
-        FJDouble.Sorter task = new FJDouble.Sorter(a, new double[a.length],
-                                                   fromIndex, nelements, gran);
-        task.invoke();
-    }
-
-    /*
-     * Parallel sorting of complex type arrays.
-     */
-
-    /**
-     * Sorts the specified array of objects into ascending order, according
-     * to the {@linkplain Comparable natural ordering} of its elements.
-     * All elements in the array must implement the {@link Comparable}
-     * interface.  Furthermore, all elements in the array must be
-     * <i>mutually comparable</i> (that is, {@code e1.compareTo(e2)} must
-     * not throw a {@code ClassCastException} for any elements {@code e1}
-     * and {@code e2} in the array).
-     *
-     * <p>This sort is not guaranteed to be <i>stable</i>:  equal elements
-     * may be reordered as a result of the sort.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(Object[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     *
-     * @throws ClassCastException if the array contains elements that are not
-     *         <i>mutually comparable</i> (for example, strings and integers)
-     * @throws IllegalArgumentException (optional) if the natural
-     *         ordering of the array elements is found to violate the
-     *         {@link Comparable} contract
-     *
-     * @since 1.8
-     */
-    public static <T extends Comparable<? super T>> void parallelSort(T[] a) {
-        parallelSort(a, 0, a.length);
-    }
-
-    /**
-     * Sorts the specified range of the specified array of objects into
-     * ascending order, according to the
-     * {@linkplain Comparable natural ordering} of its
-     * elements.  The range to be sorted extends from index
-     * {@code fromIndex}, inclusive, to index {@code toIndex}, exclusive.
-     * (If {@code fromIndex==toIndex}, the range to be sorted is empty.)  All
-     * elements in this range must implement the {@link Comparable}
-     * interface.  Furthermore, all elements in this range must be <i>mutually
-     * comparable</i> (that is, {@code e1.compareTo(e2)} must not throw a
-     * {@code ClassCastException} for any elements {@code e1} and
-     * {@code e2} in the array).
-     *
-     * <p>This sort is not guaranteed to be <i>stable</i>:  equal elements
-     * may be reordered as a result of the sort.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(Object[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element (inclusive) to be
-     *        sorted
-     * @param toIndex the index of the last element (exclusive) to be sorted
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex} or
-     *         (optional) if the natural ordering of the array elements is
-     *         found to violate the {@link Comparable} contract
-     * @throws ArrayIndexOutOfBoundsException if {@code fromIndex < 0} or
-     *         {@code toIndex > a.length}
-     * @throws ClassCastException if the array contains elements that are
-     *         not <i>mutually comparable</i> (for example, strings and
-     *         integers).
-     *
-     * @since 1.8
-     */
-    public static <T extends Comparable<? super T>>
-            void parallelSort(T[] a, int fromIndex, int toIndex) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        Class<?> tc = a.getClass().getComponentType();
-        @SuppressWarnings("unchecked")
-        T[] workspace = (T[])Array.newInstance(tc, a.length);
-        int gran = getSplitThreshold(nelements);
-        FJComparable.Sorter<T> task = new FJComparable.Sorter<>(a, workspace,
-                                                                fromIndex,
-                                                                nelements, gran);
-        task.invoke();
-    }
-
-    /**
-     * Sorts the specified array of objects according to the order induced by
-     * the specified comparator.  All elements in the array must be
-     * <i>mutually comparable</i> by the specified comparator (that is,
-     * {@code c.compare(e1, e2)} must not throw a {@code ClassCastException}
-     * for any elements {@code e1} and {@code e2} in the array).
-     *
-     * <p>This sort is not guaranteed to be <i>stable</i>:  equal elements
-     * may be reordered as a result of the sort.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(Object[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param c the comparator to determine the order of the array.  A
-     *        {@code null} value indicates that the elements'
-     *        {@linkplain Comparable natural ordering} should be used.
-     * @throws ClassCastException if the array contains elements that are
-     *         not <i>mutually comparable</i> using the specified comparator
-     * @throws IllegalArgumentException (optional) if the comparator is
-     *         found to violate the {@link java.util.Comparator} contract
-     *
-     * @since 1.8
-     */
-    public static <T> void parallelSort(T[] a, Comparator<? super T> c) {
-        parallelSort(a, 0, a.length, c);
-    }
-
-    /**
-     * Sorts the specified range of the specified array of objects according
-     * to the order induced by the specified comparator.  The range to be
-     * sorted extends from index {@code fromIndex}, inclusive, to index
-     * {@code toIndex}, exclusive.  (If {@code fromIndex==toIndex}, the
-     * range to be sorted is empty.)  All elements in the range must be
-     * <i>mutually comparable</i> by the specified comparator (that is,
-     * {@code c.compare(e1, e2)} must not throw a {@code ClassCastException}
-     * for any elements {@code e1} and {@code e2} in the range).
-     *
-     * <p>This sort is not guaranteed to be <i>stable</i>:  equal elements
-     * may be reordered as a result of the sort.
-     *
-     * <p>Implementation note: The sorting algorithm is a parallel sort-merge
-     * that breaks the array into sub-arrays that are themselves sorted and then
-     * merged. When the sub-array length reaches a minimum granularity, the
-     * sub-array is sorted using the appropriate {@link Arrays#sort(Object[])
-     * Arrays.sort} method. The algorithm requires a working space equal to the
-     * size of the original array. The {@link
-     * java.util.concurrent.ForkJoinPool#commonPool() ForkJoin common pool} is
-     * used to execute any parallel tasks.
-     *
-     * @param a the array to be sorted
-     * @param fromIndex the index of the first element (inclusive) to be
-     *        sorted
-     * @param toIndex the index of the last element (exclusive) to be sorted
-     * @param c the comparator to determine the order of the array.  A
-     *        {@code null} value indicates that the elements'
-     *        {@linkplain Comparable natural ordering} should be used.
-     * @throws IllegalArgumentException if {@code fromIndex > toIndex} or
-     *         (optional) if the natural ordering of the array elements is
-     *         found to violate the {@link Comparable} contract
-     * @throws ArrayIndexOutOfBoundsException if {@code fromIndex < 0} or
-     *         {@code toIndex > a.length}
-     * @throws ClassCastException if the array contains elements that are
-     *         not <i>mutually comparable</i> (for example, strings and
-     *         integers).
-     *
-     * @since 1.8
-     */
-    public static <T> void parallelSort(T[] a, int fromIndex, int toIndex,
-                                        Comparator<? super T> c) {
-        rangeCheck(a.length, fromIndex, toIndex);
-        int nelements = toIndex - fromIndex;
-        Class<?> tc = a.getClass().getComponentType();
-        @SuppressWarnings("unchecked")
-        T[] workspace = (T[])Array.newInstance(tc, a.length);
-        int gran = getSplitThreshold(nelements);
-        FJComparator.Sorter<T> task = new FJComparator.Sorter<>(a, workspace,
-                                                                fromIndex,
-                                                                nelements, gran, c);
-        task.invoke();
-    }
-
-    /**
-     * Returns the size threshold for splitting into subtasks.
-     * By default, uses about 8 times as many tasks as threads
-     *
-     * @param n number of elements in the array to be processed
-     */
-    private static int getSplitThreshold(int n) {
-        int p = java.util.concurrent.ForkJoinPool.getCommonPoolParallelism();
-        int t = (p > 1) ? (1 + n / (p << 3)) : n;
-        return t < MIN_ARRAY_SORT_GRAN ? MIN_ARRAY_SORT_GRAN : t;
-    }
-
-    /**
-     * Checks that {@code fromIndex} and {@code toIndex} are in
-     * the range and throws an appropriate exception, if they aren't.
-     */
-    private static void rangeCheck(int length, int fromIndex, int toIndex) {
-        if (fromIndex > toIndex) {
-            throw new IllegalArgumentException(
-                "fromIndex(" + fromIndex + ") > toIndex(" + toIndex + ")");
-        }
-        if (fromIndex < 0) {
-            throw new ArrayIndexOutOfBoundsException(fromIndex);
-        }
-        if (toIndex > length) {
-            throw new ArrayIndexOutOfBoundsException(toIndex);
-        }
-    }
-
     // Searching
 
     /**

--- a/src/share/classes/java/util/ArraysParallelSortHelpers.java	Thu May 23 09:48:44 2013 -0300
+++ b/src/share/classes/java/util/ArraysParallelSortHelpers.java	Wed May 29 13:22:58 2013 -0300
@@ -25,6 +25,7 @@
 package java.util;
 
 import java.util.concurrent.RecursiveAction;
+import java.util.concurrent.CountedCompleter;
 
 /**
  * Helper utilities for the parallel sort methods in Arrays.parallelSort.
@@ -44,1180 +45,966 @@
  *             c. merge them together
  *         3. merge together the two halves.
  *
- * One reason for splitting in quarters is that this guarantees
- * that the final sort is in the main array, not the workspace
- * array.  (workspace and main swap roles on each subsort step.)
- * Leaf-level sorts use a Sequential quicksort, that in turn uses
- * insertion sort if under threshold.  Otherwise it uses median of
- * three to pick pivot, and loops rather than recurses along left
- * path.
- *
+ * One reason for splitting in quarters is that this guarantees that
+ * the final sort is in the main array, not the workspace array.
+ * (workspace and main swap roles on each subsort step.)  Leaf-level
+ * sorts use the associated sequential sort.
  *
- * Merger classes perform merging for Sorter. If big enough, splits Left
- * partition in half; finds the greatest point in Right partition
- * less than the beginning of the second half of Left via binary
- * search; and then, in parallel, merges left half of Left with
- * elements of Right up to split point, and merges right half of
- * Left with elements of R past split point. At leaf, it just
- * sequentially merges. This is all messy to code; sadly we need
- * distinct versions for each type.
+ * Merger classes perform merging for Sorter.  They are structured
+ * such that if the underlying sort is stable (as is true for
+ * TimSort), then so is the full sort.  If big enough, they split the
+ * largest of the two partitions in half, find the greatest point in
+ * smaller partition less than the beginning of the second half of
+ * larger via binary search; and then merge in parallel the two
+ * partitions.  In part to ensure tasks are triggered in
+ * stability-preserving order, the current CountedCompleter design
+ * requires some little tasks to serve as place holders for triggering
+ * completion tasks.  These classes (EmptyCompleter and Relay) don't
+ * need to keep track of the arrays, and are never themselves forked,
+ * so don't hold any task state.
  *
+ * The primitive class versions (FJByte... FJDouble) are
+ * identical to each other except for type declarations.
+ *
+ * The base sequential sorts rely on non-public versions of TimSort,
+ * ComparableTimSort, and DualPivotQuicksort sort methods that accept
+ * temp workspace array slices that we will have already allocated, so
+ * avoids redundant allocation. (Except for DualPivotQuicksort byte[]
+ * sort, that does not ever use a workspace array.)
  */
 /*package*/ class ArraysParallelSortHelpers {
 
-    // RFE: we should only need a working array as large as the subarray
-    //      to be sorted, but the logic assumes that indices in the two
-    //      arrays always line-up
+    /*
+     * Style note: The task classes have a lot of parameters, that are
+     * stored as task fields and copied to local variables and used in
+     * compute() methods, We pack these into as few lines as possible,
+     * and hoist consistency checks among them before main loops, to
+     * reduce distraction.
+     */
 
-    /** byte support class */
-    static final class FJByte {
-        static final class Sorter extends RecursiveAction {
-            static final long serialVersionUID = 749471161188027634L;
-            final byte[] a;     // array to be sorted.
-            final byte[] w;     // workspace for merge
-            final int origin;   // origin of the part of array we deal with
-            final int n;        // Number of elements in (sub)arrays.
-            final int gran;     // split control
+    /**
+     * A placeholder task for Sorters, used for the lowest
+     * quartile task, that does not need to maintain array state.
+     */
+    static final class EmptyCompleter extends CountedCompleter<Void> {
+        static final long serialVersionUID = 2446542900576103244L;
+        EmptyCompleter(CountedCompleter<?> p) { super(p); }
+        public final void compute() { }
+    }
 
-            Sorter(byte[] a, byte[] w, int origin, int n, int gran) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.gran = gran;
-            }
+    /**
+     * A trigger for secondary merge of two merges
+     */
+    static final class Relay extends CountedCompleter<Void> {
+        static final long serialVersionUID = 2446542900576103244L;
+        final CountedCompleter<?> task;
+        Relay(CountedCompleter<?> task) {
+            super(null, 1);
+            this.task = task;
+        }
+        public final void compute() { }
+        public final void onCompletion(CountedCompleter<?> t) {
+            task.compute();
+        }
+    }
 
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final byte[] a = this.a;
-                final byte[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1; // half
-                    int q = n >>> 2; // lower quarter index
-                    int u = h + q;   // upper quarter
-                    FJSubSorter ls = new FJSubSorter(new Sorter(a, w, l, q,  g),
-                                                     new Sorter(a, w, l+q, h-q, g),
-                                                     new Merger(a, w, l,   q,
-                                                                l+q, h-q, l, g, null));
-                    FJSubSorter rs = new FJSubSorter(new Sorter(a, w, l+h, q,   g),
-                                                     new Sorter(a, w, l+u, n-u, g),
-                                                     new Merger(a, w, l+h, q,
-                                                                l+u, n-u, l+h, g, null));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger(w, a, l, h,
-                               l+h, n-h, l, g, null).compute();
-                } else {
-                    DualPivotQuicksort.sort(a, l, l+n-1);   //skip rangeCheck
+    /** Object + Comparator support class */
+    static final class FJObject {
+        static final class Sorter<T> extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final T[] a, w;
+            final int base, size, wbase, gran;
+            Comparator<? super T> comparator;
+            Sorter(CountedCompleter<?> par, T[] a, T[] w, int base, int size,
+                   int wbase, int gran,
+                   Comparator<? super T> comparator) {
+                super(par);
+                this.a = a; this.w = w; this.base = base; this.size = size;
+                this.wbase = wbase; this.gran = gran;
+                this.comparator = comparator;
+            }
+            public final void compute() {
+                CountedCompleter<?> s = this;
+                Comparator<? super T> c = this.comparator;
+                T[] a = this.a, w = this.w; // localize all params
+                int b = this.base, n = this.size, wb = this.wbase, g = this.gran;
+                while (n > g) {
+                    int h = n >>> 1, q = h >>> 1, u = h + q; // quartiles
+                    Relay fc = new Relay(new Merger<T>(s, w, a, wb, h,
+                                                       wb+h, n-h, b, g, c));
+                    Relay rc = new Relay(new Merger<T>(fc, a, w, b+h, q,
+                                                       b+u, n-u, wb+h, g, c));
+                    new Sorter<T>(rc, a, w, b+u, n-u, wb+u, g, c).fork();
+                    new Sorter<T>(rc, a, w, b+h, q, wb+h, g, c).fork();;
+                    Relay bc = new Relay(new Merger<T>(fc, a, w, b, q,
+                                                       b+q, h-q, wb, g, c));
+                    new Sorter<T>(bc, a, w, b+q, h-q, wb+q, g, c).fork();
+                    s = new EmptyCompleter(bc);
+                    n = q;
                 }
+                TimSort.sort(a, b, b + n, c, w, wb, n);
+                s.tryComplete();
             }
         }
 
-        static final class Merger extends RecursiveAction {
-            static final long serialVersionUID = -9090258248781844470L;
-            final byte[] a;
-            final byte[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger next;
+        static final class Merger<T> extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final T[] a, w; // main and workspace arrays
+            final int lbase, lsize, rbase, rsize, wbase, gran;
+            Comparator<? super T> comparator;
+            Merger(CountedCompleter<?> par, T[] a, T[] w,
+                   int lbase, int lsize, int rbase,
+                   int rsize, int wbase, int gran,
+                   Comparator<? super T> comparator) {
+                super(par);
+                this.a = a; this.w = w;
+                this.lbase = lbase; this.lsize = lsize;
+                this.rbase = rbase; this.rsize = rsize;
+                this.wbase = wbase; this.gran = gran;
+                this.comparator = comparator;
+            }
 
-            Merger(byte[] a, byte[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger next) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
+            public final void compute() {
+                Comparator<? super T> c = this.comparator;
+                T[] a = this.a, w = this.w; // localize all params
+                int lb = this.lbase, ln = this.lsize, rb = this.rbase,
+                    rn = this.rsize, k = this.wbase, g = this.gran;
+                if (a == null || w == null || lb < 0 || rb < 0 || k < 0 ||
+                    c == null)
+                    throw new IllegalStateException(); // hoist checks
+                for (int lh, rh;;) {  // split larger, find point in smaller
+                    if (ln >= rn) {
+                        if (ln <= g)
+                            break;
+                        rh = rn;
+                        T split = a[(lh = ln >>> 1) + lb];
+                        for (int lo = 0; lo < rh; ) {
+                            int rm = (lo + rh) >>> 1;
+                            if (c.compare(split, a[rm + rb]) <= 0)
+                                rh = rm;
+                            else
+                                lo = rm + 1;
+                        }
+                    }
+                    else {
+                        if (rn <= g)
+                            break;
+                        lh = ln;
+                        T split = a[(rh = rn >>> 1) + rb];
+                        for (int lo = 0; lo < lh; ) {
+                            int lm = (lo + lh) >>> 1;
+                            if (c.compare(split, a[lm + lb]) <= 0)
+                                lh = lm;
+                            else
+                                lo = lm + 1;
+                        }
+                    }
+                    Merger<T> m = new Merger<T>(this, a, w, lb + lh, ln - lh,
+                                                rb + rh, rn - rh,
+                                                k + lh + rh, g, c);
+                    rn = rh;
+                    ln = lh;
+                    addToPendingCount(1);
+                    m.fork();
+                }
+
+                int lf = lb + ln, rf = rb + rn; // index bounds
+                while (lb < lf && rb < rf) {
+                    T t, al, ar;
+                    if (c.compare((al = a[lb]), (ar = a[rb])) <= 0) {
+                        lb++; t = al;
+                    }
+                    else {
+                        rb++; t = ar;
+                    }
+                    w[k++] = t;
+                }
+                if (rb < rf)
+                    System.arraycopy(a, rb, w, k, rf - rb);
+                else if (lb < lf)
+                    System.arraycopy(a, lb, w, k, lf - lb);
+
+                tryComplete();
             }
 
-            public void compute() {
-                final byte[] a = this.a;
-                final byte[] w = this.w;
-                Merger rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    byte split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (split <= a[ro + mid])
-                            rh = mid;
-                        else
-                            rl = mid + 1;
+        }
+    } // FJObject
+
+    /** byte support class */
+    static final class FJByte {
+        static final class Sorter extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final byte[] a, w;
+            final int base, size, wbase, gran;
+            Sorter(CountedCompleter<?> par, byte[] a, byte[] w, int base,
+                   int size, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w; this.base = base; this.size = size;
+                this.wbase = wbase; this.gran = gran;
+            }
+            public final void compute() {
+                CountedCompleter<?> s = this;
+                byte[] a = this.a, w = this.w; // localize all params
+                int b = this.base, n = this.size, wb = this.wbase, g = this.gran;
+                while (n > g) {
+                    int h = n >>> 1, q = h >>> 1, u = h + q; // quartiles
+                    Relay fc = new Relay(new Merger(s, w, a, wb, h,
+                                                    wb+h, n-h, b, g));
+                    Relay rc = new Relay(new Merger(fc, a, w, b+h, q,
+                                                    b+u, n-u, wb+h, g));
+                    new Sorter(rc, a, w, b+u, n-u, wb+u, g).fork();
+                    new Sorter(rc, a, w, b+h, q, wb+h, g).fork();;
+                    Relay bc = new Relay(new Merger(fc, a, w, b, q,
+                                                    b+q, h-q, wb, g));
+                    new Sorter(bc, a, w, b+q, h-q, wb+q, g).fork();
+                    s = new EmptyCompleter(bc);
+                    n = q;
+                }
+                DualPivotQuicksort.sort(a, b, b + n - 1);
+                s.tryComplete();
+            }
+        }
+
+        static final class Merger extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final byte[] a, w; // main and workspace arrays
+            final int lbase, lsize, rbase, rsize, wbase, gran;
+            Merger(CountedCompleter<?> par, byte[] a, byte[] w,
+                   int lbase, int lsize, int rbase,
+                   int rsize, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w;
+                this.lbase = lbase; this.lsize = lsize;
+                this.rbase = rbase; this.rsize = rsize;
+                this.wbase = wbase; this.gran = gran;
+            }
+
+            public final void compute() {
+                byte[] a = this.a, w = this.w; // localize all params
+                int lb = this.lbase, ln = this.lsize, rb = this.rbase,
+                    rn = this.rsize, k = this.wbase, g = this.gran;
+                if (a == null || w == null || lb < 0 || rb < 0 || k < 0)
+                    throw new IllegalStateException(); // hoist checks
+                for (int lh, rh;;) {  // split larger, find point in smaller
+                    if (ln >= rn) {
+                        if (ln <= g)
+                            break;
+                        rh = rn;
+                        byte split = a[(lh = ln >>> 1) + lb];
+                        for (int lo = 0; lo < rh; ) {
+                            int rm = (lo + rh) >>> 1;
+                            if (split <= a[rm + rb])
+                                rh = rm;
+                            else
+                                lo = rm + 1;
+                        }
                     }
-                    (rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
-                                         nright-rh, wo+lh+rh, gran, rights)).fork();
-                    nleft = lh;
-                    nright = rh;
+                    else {
+                        if (rn <= g)
+                            break;
+                        lh = ln;
+                        byte split = a[(rh = rn >>> 1) + rb];
+                        for (int lo = 0; lo < lh; ) {
+                            int lm = (lo + lh) >>> 1;
+                            if (split <= a[lm + lb])
+                                lh = lm;
+                            else
+                                lo = lm + 1;
+                        }
+                    }
+                    Merger m = new Merger(this, a, w, lb + lh, ln - lh,
+                                          rb + rh, rn - rh,
+                                          k + lh + rh, g);
+                    rn = rh;
+                    ln = lh;
+                    addToPendingCount(1);
+                    m.fork();
                 }
 
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    byte al = a[l];
-                    byte ar = a[r];
-                    byte t;
-                    if (al <= ar) {++l; t=al;} else {++r; t = ar;}
+                int lf = lb + ln, rf = rb + rn; // index bounds
+                while (lb < lf && rb < rf) {
+                    byte t, al, ar;
+                    if ((al = a[lb]) <= (ar = a[rb])) {
+                        lb++; t = al;
+                    }
+                    else {
+                        rb++; t = ar;
+                    }
                     w[k++] = t;
                 }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
+                if (rb < rf)
+                    System.arraycopy(a, rb, w, k, rf - rb);
+                else if (lb < lf)
+                    System.arraycopy(a, lb, w, k, lf - lb);
+                tryComplete();
             }
         }
     } // FJByte
 
     /** char support class */
     static final class FJChar {
-        static final class Sorter extends RecursiveAction {
-            static final long serialVersionUID = 8723376019074596641L;
-            final char[] a;     // array to be sorted.
-            final char[] w;     // workspace for merge
-            final int origin;   // origin of the part of array we deal with
-            final int n;        // Number of elements in (sub)arrays.
-            final int gran;     // split control
-
-            Sorter(char[] a, char[] w, int origin, int n, int gran) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.gran = gran;
+        static final class Sorter extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final char[] a, w;
+            final int base, size, wbase, gran;
+            Sorter(CountedCompleter<?> par, char[] a, char[] w, int base,
+                   int size, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w; this.base = base; this.size = size;
+                this.wbase = wbase; this.gran = gran;
             }
-
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final char[] a = this.a;
-                final char[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1; // half
-                    int q = n >>> 2; // lower quarter index
-                    int u = h + q;   // upper quarter
-                    FJSubSorter ls = new FJSubSorter(new Sorter(a, w, l, q,   g),
-                                                     new Sorter(a, w, l+q, h-q, g),
-                                                     new Merger(a, w, l,   q,
-                                                                l+q, h-q, l, g, null));
-                    FJSubSorter rs = new FJSubSorter(new Sorter(a, w, l + h, q,   g),
-                                                     new Sorter(a, w, l+u, n-u, g),
-                                                     new Merger(a, w, l+h, q,
-                                                                l+u, n-u, l+h, g, null));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger(w, a, l, h, l + h, n - h, l, g, null).compute();
-                } else {
-                    DualPivotQuicksort.sort(a, l, l+n-1);   // skip rangeCheck
+            public final void compute() {
+                CountedCompleter<?> s = this;
+                char[] a = this.a, w = this.w; // localize all params
+                int b = this.base, n = this.size, wb = this.wbase, g = this.gran;
+                while (n > g) {
+                    int h = n >>> 1, q = h >>> 1, u = h + q; // quartiles
+                    Relay fc = new Relay(new Merger(s, w, a, wb, h,
+                                                    wb+h, n-h, b, g));
+                    Relay rc = new Relay(new Merger(fc, a, w, b+h, q,
+                                                    b+u, n-u, wb+h, g));
+                    new Sorter(rc, a, w, b+u, n-u, wb+u, g).fork();
+                    new Sorter(rc, a, w, b+h, q, wb+h, g).fork();;
+                    Relay bc = new Relay(new Merger(fc, a, w, b, q,
+                                                    b+q, h-q, wb, g));
+                    new Sorter(bc, a, w, b+q, h-q, wb+q, g).fork();
+                    s = new EmptyCompleter(bc);
+                    n = q;
                 }
+                DualPivotQuicksort.sort(a, b, b + n - 1, w, wb, n);
+                s.tryComplete();
             }
         }
 
-        static final class Merger extends RecursiveAction {
-            static final long serialVersionUID = -1383975444621698926L;
-            final char[] a;
-            final char[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger next;
-
-            Merger(char[] a, char[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger next) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
+        static final class Merger extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final char[] a, w; // main and workspace arrays
+            final int lbase, lsize, rbase, rsize, wbase, gran;
+            Merger(CountedCompleter<?> par, char[] a, char[] w,
+                   int lbase, int lsize, int rbase,
+                   int rsize, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w;
+                this.lbase = lbase; this.lsize = lsize;
+                this.rbase = rbase; this.rsize = rsize;
+                this.wbase = wbase; this.gran = gran;
             }
 
-            public void compute() {
-                final char[] a = this.a;
-                final char[] w = this.w;
-                Merger rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    char split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (split <= a[ro + mid])
-                            rh = mid;
-                        else
-                            rl = mid + 1;
+            public final void compute() {
+                char[] a = this.a, w = this.w; // localize all params
+                int lb = this.lbase, ln = this.lsize, rb = this.rbase,
+                    rn = this.rsize, k = this.wbase, g = this.gran;
+                if (a == null || w == null || lb < 0 || rb < 0 || k < 0)
+                    throw new IllegalStateException(); // hoist checks
+                for (int lh, rh;;) {  // split larger, find point in smaller
+                    if (ln >= rn) {
+                        if (ln <= g)
+                            break;
+                        rh = rn;
+                        char split = a[(lh = ln >>> 1) + lb];
+                        for (int lo = 0; lo < rh; ) {
+                            int rm = (lo + rh) >>> 1;
+                            if (split <= a[rm + rb])
+                                rh = rm;
+                            else
+                                lo = rm + 1;
+                        }
                     }
-                    (rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
-                                         nright-rh, wo+lh+rh, gran, rights)).fork();
-                    nleft = lh;
-                    nright = rh;
+                    else {
+                        if (rn <= g)
+                            break;
+                        lh = ln;
+                        char split = a[(rh = rn >>> 1) + rb];
+                        for (int lo = 0; lo < lh; ) {
+                            int lm = (lo + lh) >>> 1;
+                            if (split <= a[lm + lb])
+                                lh = lm;
+                            else
+                                lo = lm + 1;
+                        }
+                    }
+                    Merger m = new Merger(this, a, w, lb + lh, ln - lh,
+                                          rb + rh, rn - rh,
+                                          k + lh + rh, g);
+                    rn = rh;
+                    ln = lh;
+                    addToPendingCount(1);
+                    m.fork();
                 }
 
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    char al = a[l];
-                    char ar = a[r];
-                    char t;
-                    if (al <= ar) {++l; t=al;} else {++r; t = ar;}
+                int lf = lb + ln, rf = rb + rn; // index bounds
+                while (lb < lf && rb < rf) {
+                    char t, al, ar;
+                    if ((al = a[lb]) <= (ar = a[rb])) {
+                        lb++; t = al;
+                    }
+                    else {
+                        rb++; t = ar;
+                    }
                     w[k++] = t;
                 }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
+                if (rb < rf)
+                    System.arraycopy(a, rb, w, k, rf - rb);
+                else if (lb < lf)
+                    System.arraycopy(a, lb, w, k, lf - lb);
+                tryComplete();
             }
         }
     } // FJChar
 
     /** short support class */
     static final class FJShort {
-        static final class Sorter extends RecursiveAction {
-            static final long serialVersionUID = -7886754793730583084L;
-            final short[] a;    // array to be sorted.
-            final short[] w;    // workspace for merge
-            final int origin;   // origin of the part of array we deal with
-            final int n;        // Number of elements in (sub)arrays.
-            final int gran;     // split control
-
-            Sorter(short[] a, short[] w, int origin, int n, int gran) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.gran = gran;
+        static final class Sorter extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final short[] a, w;
+            final int base, size, wbase, gran;
+            Sorter(CountedCompleter<?> par, short[] a, short[] w, int base,
+                   int size, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w; this.base = base; this.size = size;
+                this.wbase = wbase; this.gran = gran;
             }
-
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final short[] a = this.a;
-                final short[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1; // half
-                    int q = n >>> 2; // lower quarter index
-                    int u = h + q;   // upper quarter
-                    FJSubSorter ls = new FJSubSorter(new Sorter(a, w, l, q,   g),
-                                                     new Sorter(a, w, l+q, h-q, g),
-                                                     new Merger(a, w, l,   q,
-                                                                l+q, h-q, l, g, null));
-                    FJSubSorter rs = new FJSubSorter(new Sorter(a, w, l + h, q,   g),
-                                                     new Sorter(a, w, l+u, n-u, g),
-                                                     new Merger(a, w, l+h, q,
-                                                                l+u, n-u, l+h, g, null));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger(w, a, l, h, l + h, n - h, l, g, null).compute();
-                } else {
-                    DualPivotQuicksort.sort(a, l, l+n-1);   // skip rangeCheck
+            public final void compute() {
+                CountedCompleter<?> s = this;
+                short[] a = this.a, w = this.w; // localize all params
+                int b = this.base, n = this.size, wb = this.wbase, g = this.gran;
+                while (n > g) {
+                    int h = n >>> 1, q = h >>> 1, u = h + q; // quartiles
+                    Relay fc = new Relay(new Merger(s, w, a, wb, h,
+                                                    wb+h, n-h, b, g));
+                    Relay rc = new Relay(new Merger(fc, a, w, b+h, q,
+                                                    b+u, n-u, wb+h, g));
+                    new Sorter(rc, a, w, b+u, n-u, wb+u, g).fork();
+                    new Sorter(rc, a, w, b+h, q, wb+h, g).fork();;
+                    Relay bc = new Relay(new Merger(fc, a, w, b, q,
+                                                    b+q, h-q, wb, g));
+                    new Sorter(bc, a, w, b+q, h-q, wb+q, g).fork();
+                    s = new EmptyCompleter(bc);
+                    n = q;
                 }
+                DualPivotQuicksort.sort(a, b, b + n - 1, w, wb, n);
+                s.tryComplete();
             }
         }
 
-        static final class Merger extends RecursiveAction {
-            static final long serialVersionUID = 3895749408536700048L;
-            final short[] a;
-            final short[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger next;
-
-            Merger(short[] a, short[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger next) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
+        static final class Merger extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final short[] a, w; // main and workspace arrays
+            final int lbase, lsize, rbase, rsize, wbase, gran;
+            Merger(CountedCompleter<?> par, short[] a, short[] w,
+                   int lbase, int lsize, int rbase,
+                   int rsize, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w;
+                this.lbase = lbase; this.lsize = lsize;
+                this.rbase = rbase; this.rsize = rsize;
+                this.wbase = wbase; this.gran = gran;
             }
 
-            public void compute() {
-                final short[] a = this.a;
-                final short[] w = this.w;
-                Merger rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    short split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (split <= a[ro + mid])
-                            rh = mid;
-                        else
-                            rl = mid + 1;
+            public final void compute() {
+                short[] a = this.a, w = this.w; // localize all params
+                int lb = this.lbase, ln = this.lsize, rb = this.rbase,
+                    rn = this.rsize, k = this.wbase, g = this.gran;
+                if (a == null || w == null || lb < 0 || rb < 0 || k < 0)
+                    throw new IllegalStateException(); // hoist checks
+                for (int lh, rh;;) {  // split larger, find point in smaller
+                    if (ln >= rn) {
+                        if (ln <= g)
+                            break;
+                        rh = rn;
+                        short split = a[(lh = ln >>> 1) + lb];
+                        for (int lo = 0; lo < rh; ) {
+                            int rm = (lo + rh) >>> 1;
+                            if (split <= a[rm + rb])
+                                rh = rm;
+                            else
+                                lo = rm + 1;
+                        }
                     }
-                    (rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
-                                         nright-rh, wo+lh+rh, gran, rights)).fork();
-                    nleft = lh;
-                    nright = rh;
+                    else {
+                        if (rn <= g)
+                            break;
+                        lh = ln;
+                        short split = a[(rh = rn >>> 1) + rb];
+                        for (int lo = 0; lo < lh; ) {
+                            int lm = (lo + lh) >>> 1;
+                            if (split <= a[lm + lb])
+                                lh = lm;
+                            else
+                                lo = lm + 1;
+                        }
+                    }
+                    Merger m = new Merger(this, a, w, lb + lh, ln - lh,
+                                          rb + rh, rn - rh,
+                                          k + lh + rh, g);
+                    rn = rh;
+                    ln = lh;
+                    addToPendingCount(1);
+                    m.fork();
                 }
 
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    short al = a[l];
-                    short ar = a[r];
-                    short t;
-                    if (al <= ar) {++l; t=al;} else {++r; t = ar;}
+                int lf = lb + ln, rf = rb + rn; // index bounds
+                while (lb < lf && rb < rf) {
+                    short t, al, ar;
+                    if ((al = a[lb]) <= (ar = a[rb])) {
+                        lb++; t = al;
+                    }
+                    else {
+                        rb++; t = ar;
+                    }
                     w[k++] = t;
                 }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
+                if (rb < rf)
+                    System.arraycopy(a, rb, w, k, rf - rb);
+                else if (lb < lf)
+                    System.arraycopy(a, lb, w, k, lf - lb);
+                tryComplete();
             }
         }
     } // FJShort
 
     /** int support class */
     static final class FJInt {
-        static final class Sorter extends RecursiveAction {
-            static final long serialVersionUID = 4263311808957292729L;
-            final int[] a;     // array to be sorted.
-            final int[] w;     // workspace for merge
-            final int origin;  // origin of the part of array we deal with
-            final int n;       // Number of elements in (sub)arrays.
-            final int gran;    // split control
-
-            Sorter(int[] a, int[] w, int origin, int n, int gran) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.gran = gran;
+        static final class Sorter extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final int[] a, w;
+            final int base, size, wbase, gran;
+            Sorter(CountedCompleter<?> par, int[] a, int[] w, int base,
+                   int size, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w; this.base = base; this.size = size;
+                this.wbase = wbase; this.gran = gran;
             }
-
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final int[] a = this.a;
-                final int[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1; // half
-                    int q = n >>> 2; // lower quarter index
-                    int u = h + q;   // upper quarter
-                    FJSubSorter ls = new FJSubSorter(new Sorter(a, w, l, q,   g),
-                                                     new Sorter(a, w, l+q, h-q, g),
-                                                     new Merger(a, w, l,   q,
-                                                                l+q, h-q, l, g, null));
-                    FJSubSorter rs = new FJSubSorter(new Sorter(a, w, l + h, q,   g),
-                                                     new Sorter(a, w, l+u, n-u, g),
-                                                     new Merger(a, w, l+h, q,
-                                                                l+u, n-u, l+h, g, null));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger(w, a, l, h, l + h, n - h, l, g, null).compute();
-                } else {
-                    DualPivotQuicksort.sort(a, l, l+n-1);   // skip rangeCheck
+            public final void compute() {
+                CountedCompleter<?> s = this;
+                int[] a = this.a, w = this.w; // localize all params
+                int b = this.base, n = this.size, wb = this.wbase, g = this.gran;
+                while (n > g) {
+                    int h = n >>> 1, q = h >>> 1, u = h + q; // quartiles
+                    Relay fc = new Relay(new Merger(s, w, a, wb, h,
+                                                    wb+h, n-h, b, g));
+                    Relay rc = new Relay(new Merger(fc, a, w, b+h, q,
+                                                    b+u, n-u, wb+h, g));
+                    new Sorter(rc, a, w, b+u, n-u, wb+u, g).fork();
+                    new Sorter(rc, a, w, b+h, q, wb+h, g).fork();;
+                    Relay bc = new Relay(new Merger(fc, a, w, b, q,
+                                                    b+q, h-q, wb, g));
+                    new Sorter(bc, a, w, b+q, h-q, wb+q, g).fork();
+                    s = new EmptyCompleter(bc);
+                    n = q;
                 }
+                DualPivotQuicksort.sort(a, b, b + n - 1, w, wb, n);
+                s.tryComplete();
             }
         }
 
-        static final class Merger extends RecursiveAction {
-            static final long serialVersionUID = -8727507284219982792L;
-            final int[] a;
-            final int[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger next;
-
-            Merger(int[] a, int[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger next) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
+        static final class Merger extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final int[] a, w; // main and workspace arrays
+            final int lbase, lsize, rbase, rsize, wbase, gran;
+            Merger(CountedCompleter<?> par, int[] a, int[] w,
+                   int lbase, int lsize, int rbase,
+                   int rsize, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w;
+                this.lbase = lbase; this.lsize = lsize;
+                this.rbase = rbase; this.rsize = rsize;
+                this.wbase = wbase; this.gran = gran;
             }
 
-            public void compute() {
-                final int[] a = this.a;
-                final int[] w = this.w;
-                Merger rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    int split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (split <= a[ro + mid])
-                            rh = mid;
-                        else
-                            rl = mid + 1;
+            public final void compute() {
+                int[] a = this.a, w = this.w; // localize all params
+                int lb = this.lbase, ln = this.lsize, rb = this.rbase,
+                    rn = this.rsize, k = this.wbase, g = this.gran;
+                if (a == null || w == null || lb < 0 || rb < 0 || k < 0)
+                    throw new IllegalStateException(); // hoist checks
+                for (int lh, rh;;) {  // split larger, find point in smaller
+                    if (ln >= rn) {
+                        if (ln <= g)
+                            break;
+                        rh = rn;
+                        int split = a[(lh = ln >>> 1) + lb];
+                        for (int lo = 0; lo < rh; ) {
+                            int rm = (lo + rh) >>> 1;
+                            if (split <= a[rm + rb])
+                                rh = rm;
+                            else
+                                lo = rm + 1;
+                        }
                     }
-                    (rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
-                                         nright-rh, wo+lh+rh, gran, rights)).fork();
-                    nleft = lh;
-                    nright = rh;
+                    else {
+                        if (rn <= g)
+                            break;
+                        lh = ln;
+                        int split = a[(rh = rn >>> 1) + rb];
+                        for (int lo = 0; lo < lh; ) {
+                            int lm = (lo + lh) >>> 1;
+                            if (split <= a[lm + lb])
+                                lh = lm;
+                            else
+                                lo = lm + 1;
+                        }
+                    }
+                    Merger m = new Merger(this, a, w, lb + lh, ln - lh,
+                                          rb + rh, rn - rh,
+                                          k + lh + rh, g);
+                    rn = rh;
+                    ln = lh;
+                    addToPendingCount(1);
+                    m.fork();
                 }
 
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    int al = a[l];
-                    int ar = a[r];
-                    int t;
-                    if (al <= ar) {++l; t=al;} else {++r; t = ar;}
+                int lf = lb + ln, rf = rb + rn; // index bounds
+                while (lb < lf && rb < rf) {
+                    int t, al, ar;
+                    if ((al = a[lb]) <= (ar = a[rb])) {
+                        lb++; t = al;
+                    }
+                    else {
+                        rb++; t = ar;
+                    }
                     w[k++] = t;
                 }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
+                if (rb < rf)
+                    System.arraycopy(a, rb, w, k, rf - rb);
+                else if (lb < lf)
+                    System.arraycopy(a, lb, w, k, lf - lb);
+                tryComplete();
             }
         }
     } // FJInt
 
     /** long support class */
     static final class FJLong {
-        static final class Sorter extends RecursiveAction {
-            static final long serialVersionUID = 6553695007444392455L;
-            final long[] a;     // array to be sorted.
-            final long[] w;     // workspace for merge
-            final int origin;   // origin of the part of array we deal with
-            final int n;        // Number of elements in (sub)arrays.
-            final int gran;     // split control
-
-            Sorter(long[] a, long[] w, int origin, int n, int gran) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.gran = gran;
+        static final class Sorter extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final long[] a, w;
+            final int base, size, wbase, gran;
+            Sorter(CountedCompleter<?> par, long[] a, long[] w, int base,
+                   int size, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w; this.base = base; this.size = size;
+                this.wbase = wbase; this.gran = gran;
             }
-
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final long[] a = this.a;
-                final long[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1; // half
-                    int q = n >>> 2; // lower quarter index
-                    int u = h + q;   // upper quarter
-                    FJSubSorter ls = new FJSubSorter(new Sorter(a, w, l, q,   g),
-                                                     new Sorter(a, w, l+q, h-q, g),
-                                                     new Merger(a, w, l,   q,
-                                                                l+q, h-q, l, g, null));
-                    FJSubSorter rs = new FJSubSorter(new Sorter(a, w, l + h, q,   g),
-                                                     new Sorter(a, w, l+u, n-u, g),
-                                                     new Merger(a, w, l+h, q,
-                                                                l+u, n-u, l+h, g, null));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger(w, a, l, h, l + h, n - h, l, g, null).compute();
-                } else {
-                    DualPivotQuicksort.sort(a, l, l+n-1);   // skip rangeCheck
+            public final void compute() {
+                CountedCompleter<?> s = this;
+                long[] a = this.a, w = this.w; // localize all params
+                int b = this.base, n = this.size, wb = this.wbase, g = this.gran;
+                while (n > g) {
+                    int h = n >>> 1, q = h >>> 1, u = h + q; // quartiles
+                    Relay fc = new Relay(new Merger(s, w, a, wb, h,
+                                                    wb+h, n-h, b, g));
+                    Relay rc = new Relay(new Merger(fc, a, w, b+h, q,
+                                                    b+u, n-u, wb+h, g));
+                    new Sorter(rc, a, w, b+u, n-u, wb+u, g).fork();
+                    new Sorter(rc, a, w, b+h, q, wb+h, g).fork();;
+                    Relay bc = new Relay(new Merger(fc, a, w, b, q,
+                                                    b+q, h-q, wb, g));
+                    new Sorter(bc, a, w, b+q, h-q, wb+q, g).fork();
+                    s = new EmptyCompleter(bc);
+                    n = q;
                 }
+                DualPivotQuicksort.sort(a, b, b + n - 1, w, wb, n);
+                s.tryComplete();
             }
         }
 
-        static final class Merger extends RecursiveAction {
-            static final long serialVersionUID = 8843567516333283861L;
-            final long[] a;
-            final long[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger next;
-
-            Merger(long[] a, long[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger next) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
+        static final class Merger extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final long[] a, w; // main and workspace arrays
+            final int lbase, lsize, rbase, rsize, wbase, gran;
+            Merger(CountedCompleter<?> par, long[] a, long[] w,
+                   int lbase, int lsize, int rbase,
+                   int rsize, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w;
+                this.lbase = lbase; this.lsize = lsize;
+                this.rbase = rbase; this.rsize = rsize;
+                this.wbase = wbase; this.gran = gran;
             }
 
-            public void compute() {
-                final long[] a = this.a;
-                final long[] w = this.w;
-                Merger rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    long split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (split <= a[ro + mid])
-                            rh = mid;
-                        else
-                            rl = mid + 1;
+            public final void compute() {
+                long[] a = this.a, w = this.w; // localize all params
+                int lb = this.lbase, ln = this.lsize, rb = this.rbase,
+                    rn = this.rsize, k = this.wbase, g = this.gran;
+                if (a == null || w == null || lb < 0 || rb < 0 || k < 0)
+                    throw new IllegalStateException(); // hoist checks
+                for (int lh, rh;;) {  // split larger, find point in smaller
+                    if (ln >= rn) {
+                        if (ln <= g)
+                            break;
+                        rh = rn;
+                        long split = a[(lh = ln >>> 1) + lb];
+                        for (int lo = 0; lo < rh; ) {
+                            int rm = (lo + rh) >>> 1;
+                            if (split <= a[rm + rb])
+                                rh = rm;
+                            else
+                                lo = rm + 1;
+                        }
                     }
-                    (rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
-                      nright-rh, wo+lh+rh, gran, rights)).fork();
-                    nleft = lh;
-                    nright = rh;
+                    else {
+                        if (rn <= g)
+                            break;
+                        lh = ln;
+                        long split = a[(rh = rn >>> 1) + rb];
+                        for (int lo = 0; lo < lh; ) {
+                            int lm = (lo + lh) >>> 1;
+                            if (split <= a[lm + lb])
+                                lh = lm;
+                            else
+                                lo = lm + 1;
+                        }
+                    }
+                    Merger m = new Merger(this, a, w, lb + lh, ln - lh,
+                                          rb + rh, rn - rh,
+                                          k + lh + rh, g);
+                    rn = rh;
+                    ln = lh;
+                    addToPendingCount(1);
+                    m.fork();
                 }
 
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    long al = a[l];
-                    long ar = a[r];
-                    long t;
-                    if (al <= ar) {++l; t=al;} else {++r; t = ar;}
+                int lf = lb + ln, rf = rb + rn; // index bounds
+                while (lb < lf && rb < rf) {
+                    long t, al, ar;
+                    if ((al = a[lb]) <= (ar = a[rb])) {
+                        lb++; t = al;
+                    }
+                    else {
+                        rb++; t = ar;
+                    }
                     w[k++] = t;
                 }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
+                if (rb < rf)
+                    System.arraycopy(a, rb, w, k, rf - rb);
+                else if (lb < lf)
+                    System.arraycopy(a, lb, w, k, lf - lb);
+                tryComplete();
             }
         }
     } // FJLong
 
     /** float support class */
     static final class FJFloat {
-        static final class Sorter extends RecursiveAction {
-            static final long serialVersionUID = 1602600178202763377L;
-            final float[] a;    // array to be sorted.
-            final float[] w;    // workspace for merge
-            final int origin;   // origin of the part of array we deal with
-            final int n;        // Number of elements in (sub)arrays.
-            final int gran;     // split control
-
-            Sorter(float[] a, float[] w, int origin, int n, int gran) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.gran = gran;
+        static final class Sorter extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final float[] a, w;
+            final int base, size, wbase, gran;
+            Sorter(CountedCompleter<?> par, float[] a, float[] w, int base,
+                   int size, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w; this.base = base; this.size = size;
+                this.wbase = wbase; this.gran = gran;
             }
-
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final float[] a = this.a;
-                final float[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1; // half
-                    int q = n >>> 2; // lower quarter index
-                    int u = h + q;   // upper quarter
-                    FJSubSorter ls = new FJSubSorter(new Sorter(a, w, l, q,   g),
-                                                     new Sorter(a, w, l+q, h-q, g),
-                                                     new Merger(a, w, l,   q,
-                                                                l+q, h-q, l, g, null));
-                    FJSubSorter rs = new FJSubSorter(new Sorter(a, w, l + h, q,   g),
-                                                     new Sorter(a, w, l+u, n-u, g),
-                                                     new Merger(a, w, l+h, q,
-                                                                l+u, n-u, l+h, g, null));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger(w, a, l, h, l + h, n - h, l, g, null).compute();
-                } else {
-                    DualPivotQuicksort.sort(a, l, l+n-1);   // skip rangeCheck
+            public final void compute() {
+                CountedCompleter<?> s = this;
+                float[] a = this.a, w = this.w; // localize all params
+                int b = this.base, n = this.size, wb = this.wbase, g = this.gran;
+                while (n > g) {
+                    int h = n >>> 1, q = h >>> 1, u = h + q; // quartiles
+                    Relay fc = new Relay(new Merger(s, w, a, wb, h,
+                                                    wb+h, n-h, b, g));
+                    Relay rc = new Relay(new Merger(fc, a, w, b+h, q,
+                                                    b+u, n-u, wb+h, g));
+                    new Sorter(rc, a, w, b+u, n-u, wb+u, g).fork();
+                    new Sorter(rc, a, w, b+h, q, wb+h, g).fork();;
+                    Relay bc = new Relay(new Merger(fc, a, w, b, q,
+                                                    b+q, h-q, wb, g));
+                    new Sorter(bc, a, w, b+q, h-q, wb+q, g).fork();
+                    s = new EmptyCompleter(bc);
+                    n = q;
                 }
+                DualPivotQuicksort.sort(a, b, b + n - 1, w, wb, n);
+                s.tryComplete();
             }
         }
 
-        static final class Merger extends RecursiveAction {
-            static final long serialVersionUID = 1518176433845397426L;
-            final float[] a;
-            final float[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger next;
-
-            Merger(float[] a, float[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger next) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
+        static final class Merger extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final float[] a, w; // main and workspace arrays
+            final int lbase, lsize, rbase, rsize, wbase, gran;
+            Merger(CountedCompleter<?> par, float[] a, float[] w,
+                   int lbase, int lsize, int rbase,
+                   int rsize, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w;
+                this.lbase = lbase; this.lsize = lsize;
+                this.rbase = rbase; this.rsize = rsize;
+                this.wbase = wbase; this.gran = gran;
             }
 
-            public void compute() {
-                final float[] a = this.a;
-                final float[] w = this.w;
-                Merger rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    float split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (Float.compare(split, a[ro+mid]) <= 0)
-                            rh = mid;
-                        else
-                            rl = mid + 1;
+            public final void compute() {
+                float[] a = this.a, w = this.w; // localize all params
+                int lb = this.lbase, ln = this.lsize, rb = this.rbase,
+                    rn = this.rsize, k = this.wbase, g = this.gran;
+                if (a == null || w == null || lb < 0 || rb < 0 || k < 0)
+                    throw new IllegalStateException(); // hoist checks
+                for (int lh, rh;;) {  // split larger, find point in smaller
+                    if (ln >= rn) {
+                        if (ln <= g)
+                            break;
+                        rh = rn;
+                        float split = a[(lh = ln >>> 1) + lb];
+                        for (int lo = 0; lo < rh; ) {
+                            int rm = (lo + rh) >>> 1;
+                            if (split <= a[rm + rb])
+                                rh = rm;
+                            else
+                                lo = rm + 1;
+                        }
                     }
-                    (rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
-                                         nright-rh, wo+lh+rh, gran, rights)).fork();
-                    nleft = lh;
-                    nright = rh;
+                    else {
+                        if (rn <= g)
+                            break;
+                        lh = ln;
+                        float split = a[(rh = rn >>> 1) + rb];
+                        for (int lo = 0; lo < lh; ) {
+                            int lm = (lo + lh) >>> 1;
+                            if (split <= a[lm + lb])
+                                lh = lm;
+                            else
+                                lo = lm + 1;
+                        }
+                    }
+                    Merger m = new Merger(this, a, w, lb + lh, ln - lh,
+                                          rb + rh, rn - rh,
+                                          k + lh + rh, g);
+                    rn = rh;
+                    ln = lh;
+                    addToPendingCount(1);
+                    m.fork();
                 }
 
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    float al = a[l];
-                    float ar = a[r];
-                    float t;
-                    if (Float.compare(al, ar) <= 0) {
-                        ++l;
-                        t = al;
-                    } else {
-                        ++r;
-                        t = ar;
+                int lf = lb + ln, rf = rb + rn; // index bounds
+                while (lb < lf && rb < rf) {
+                    float t, al, ar;
+                    if ((al = a[lb]) <= (ar = a[rb])) {
+                        lb++; t = al;
+                    }
+                    else {
+                        rb++; t = ar;
                     }
                     w[k++] = t;
                 }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
+                if (rb < rf)
+                    System.arraycopy(a, rb, w, k, rf - rb);
+                else if (lb < lf)
+                    System.arraycopy(a, lb, w, k, lf - lb);
+                tryComplete();
             }
         }
     } // FJFloat
 
     /** double support class */
     static final class FJDouble {
-        static final class Sorter extends RecursiveAction {
+        static final class Sorter extends CountedCompleter<Void> {
             static final long serialVersionUID = 2446542900576103244L;
-            final double[] a;    // array to be sorted.
-            final double[] w;    // workspace for merge
-            final int origin;    // origin of the part of array we deal with
-            final int n;         // Number of elements in (sub)arrays.
-            final int gran;      // split control
-
-            Sorter(double[] a, double[] w, int origin, int n, int gran) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.gran = gran;
+            final double[] a, w;
+            final int base, size, wbase, gran;
+            Sorter(CountedCompleter<?> par, double[] a, double[] w, int base,
+                   int size, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w; this.base = base; this.size = size;
+                this.wbase = wbase; this.gran = gran;
             }
-
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final double[] a = this.a;
-                final double[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1; // half
-                    int q = n >>> 2; // lower quarter index
-                    int u = h + q;   // upper quarter
-                    FJSubSorter ls = new FJSubSorter(new Sorter(a, w, l, q,   g),
-                                                     new Sorter(a, w, l+q, h-q, g),
-                                                     new Merger(a, w, l,   q,
-                                                                l+q, h-q, l, g, null));
-                    FJSubSorter rs = new FJSubSorter(new Sorter(a, w, l + h, q,   g),
-                                                     new Sorter(a, w, l+u, n-u, g),
-                                                     new Merger(a, w, l+h, q,
-                                                                l+u, n-u, l+h, g, null));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger(w, a, l, h, l + h, n - h, l, g, null).compute();
-                } else {
-                    DualPivotQuicksort.sort(a, l, l+n-1);   // skip rangeCheck
+            public final void compute() {
+                CountedCompleter<?> s = this;
+                double[] a = this.a, w = this.w; // localize all params
+                int b = this.base, n = this.size, wb = this.wbase, g = this.gran;
+                while (n > g) {
+                    int h = n >>> 1, q = h >>> 1, u = h + q; // quartiles
+                    Relay fc = new Relay(new Merger(s, w, a, wb, h,
+                                                    wb+h, n-h, b, g));
+                    Relay rc = new Relay(new Merger(fc, a, w, b+h, q,
+                                                    b+u, n-u, wb+h, g));
+                    new Sorter(rc, a, w, b+u, n-u, wb+u, g).fork();
+                    new Sorter(rc, a, w, b+h, q, wb+h, g).fork();;
+                    Relay bc = new Relay(new Merger(fc, a, w, b, q,
+                                                    b+q, h-q, wb, g));
+                    new Sorter(bc, a, w, b+q, h-q, wb+q, g).fork();
+                    s = new EmptyCompleter(bc);
+                    n = q;
                 }
+                DualPivotQuicksort.sort(a, b, b + n - 1, w, wb, n);
+                s.tryComplete();
             }
         }
 
-        static final class Merger extends RecursiveAction {
-            static final long serialVersionUID = 8076242187166127592L;
-            final double[] a;
-            final double[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger next;
-
-            Merger(double[] a, double[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger next) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
+        static final class Merger extends CountedCompleter<Void> {
+            static final long serialVersionUID = 2446542900576103244L;
+            final double[] a, w; // main and workspace arrays
+            final int lbase, lsize, rbase, rsize, wbase, gran;
+            Merger(CountedCompleter<?> par, double[] a, double[] w,
+                   int lbase, int lsize, int rbase,
+                   int rsize, int wbase, int gran) {
+                super(par);
+                this.a = a; this.w = w;
+                this.lbase = lbase; this.lsize = lsize;
+                this.rbase = rbase; this.rsize = rsize;
+                this.wbase = wbase; this.gran = gran;
             }
 
-            public void compute() {
-                final double[] a = this.a;
-                final double[] w = this.w;
-                Merger rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    double split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (Double.compare(split, a[ro+mid]) <= 0)
-                            rh = mid;
-                        else
-                            rl = mid + 1;
+            public final void compute() {
+                double[] a = this.a, w = this.w; // localize all params
+                int lb = this.lbase, ln = this.lsize, rb = this.rbase,
+                    rn = this.rsize, k = this.wbase, g = this.gran;
+                if (a == null || w == null || lb < 0 || rb < 0 || k < 0)
+                    throw new IllegalStateException(); // hoist checks
+                for (int lh, rh;;) {  // split larger, find point in smaller
+                    if (ln >= rn) {
+                        if (ln <= g)
+                            break;
+                        rh = rn;
+                        double split = a[(lh = ln >>> 1) + lb];
+                        for (int lo = 0; lo < rh; ) {
+                            int rm = (lo + rh) >>> 1;
+                            if (split <= a[rm + rb])
+                                rh = rm;
+                            else
+                                lo = rm + 1;
+                        }
                     }
-                    (rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
-                                         nright-rh, wo+lh+rh, gran, rights)).fork();
-                    nleft = lh;
-                    nright = rh;
+                    else {
+                        if (rn <= g)
+                            break;
+                        lh = ln;
+                        double split = a[(rh = rn >>> 1) + rb];
+                        for (int lo = 0; lo < lh; ) {
+                            int lm = (lo + lh) >>> 1;
+                            if (split <= a[lm + lb])
+                                lh = lm;
+                            else
+                                lo = lm + 1;
+                        }
+                    }
+                    Merger m = new Merger(this, a, w, lb + lh, ln - lh,
+                                          rb + rh, rn - rh,
+                                          k + lh + rh, g);
+                    rn = rh;
+                    ln = lh;
+                    addToPendingCount(1);
+                    m.fork();
                 }
 
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    double al = a[l];
-                    double ar = a[r];
-                    double t;
-                    if (Double.compare(al, ar) <= 0) {
-                        ++l;
-                        t = al;
-                    } else {
-                        ++r;
-                        t = ar;
+                int lf = lb + ln, rf = rb + rn; // index bounds
+                while (lb < lf && rb < rf) {
+                    double t, al, ar;
+                    if ((al = a[lb]) <= (ar = a[rb])) {
+                        lb++; t = al;
+                    }
+                    else {
+                        rb++; t = ar;
                     }
                     w[k++] = t;
                 }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
+                if (rb < rf)
+                    System.arraycopy(a, rb, w, k, rf - rb);
+                else if (lb < lf)
+                    System.arraycopy(a, lb, w, k, lf - lb);
+                tryComplete();
             }
         }
     } // FJDouble
 
-    /** Comparable support class */
-    static final class FJComparable {
-        static final class Sorter<T extends Comparable<? super T>> extends RecursiveAction {
-            static final long serialVersionUID = -1024003289463302522L;
-            final T[] a;
-            final T[] w;
-            final int origin;
-            final int n;
-            final int gran;
-
-            Sorter(T[] a, T[] w, int origin, int n, int gran) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.gran = gran;
-            }
-
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final T[] a = this.a;
-                final T[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1;
-                    int q = n >>> 2;
-                    int u = h + q;
-                    FJSubSorter ls = new FJSubSorter(new Sorter<>(a, w, l, q,   g),
-                                                     new Sorter<>(a, w, l+q, h-q, g),
-                                                     new Merger<>(a, w, l,   q,
-                                                                  l+q, h-q, l, g, null));
-                    FJSubSorter rs = new FJSubSorter(new Sorter<>(a, w, l+h, q,   g),
-                                                     new Sorter<>(a, w, l+u, n-u, g),
-                                                     new Merger<>(a, w, l+h, q,
-                                                                  l+u, n-u, l+h, g, null));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger<>(w, a, l, h, l + h, n - h, l, g, null).compute();
-                } else {
-                    Arrays.sort(a, l, l+n);
-                }
-            }
-        }
-
-        static final class Merger<T extends Comparable<? super T>> extends RecursiveAction {
-            static final long serialVersionUID = -3989771675258379302L;
-            final T[] a;
-            final T[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger<T> next;
-
-            Merger(T[] a, T[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger<T> next) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
-            }
-
-            public void compute() {
-                final T[] a = this.a;
-                final T[] w = this.w;
-                Merger<T> rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    T split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (split.compareTo(a[ro + mid]) <= 0)
-                            rh = mid;
-                        else
-                            rl = mid + 1;
-                    }
-                    (rights = new Merger<>(a, w, splitIndex, nleft-lh, ro+rh,
-                                           nright-rh, wo+lh+rh, gran, rights)).fork();
-                    nleft = lh;
-                    nright = rh;
-                }
-
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    T al = a[l];
-                    T ar = a[r];
-                    T t;
-                    if (al.compareTo(ar) <= 0) {++l; t=al;} else {++r; t=ar; }
-                    w[k++] = t;
-                }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
-            }
-        }
-    } // FJComparable
-
-    /** Object + Comparator support class */
-    static final class FJComparator {
-        static final class Sorter<T> extends RecursiveAction {
-            static final long serialVersionUID = 9191600840025808581L;
-            final T[] a;       // array to be sorted.
-            final T[] w;       // workspace for merge
-            final int origin;  // origin of the part of array we deal with
-            final int n;       // Number of elements in (sub)arrays.
-            final int gran;    // split control
-            final Comparator<? super T> cmp; // Comparator to use
-
-            Sorter(T[] a, T[] w, int origin, int n, int gran, Comparator<? super T> cmp) {
-                this.a = a;
-                this.w = w;
-                this.origin = origin;
-                this.n = n;
-                this.cmp = cmp;
-                this.gran = gran;
-            }
-
-            public void compute() {
-                final int l = origin;
-                final int g = gran;
-                final int n = this.n;
-                final T[] a = this.a;
-                final T[] w = this.w;
-                if (n > g) {
-                    int h = n >>> 1; // half
-                    int q = n >>> 2; // lower quarter index
-                    int u = h + q;   // upper quarter
-                    FJSubSorter ls = new FJSubSorter(new Sorter<>(a, w, l, q,   g, cmp),
-                                                     new Sorter<>(a, w, l+q, h-q, g, cmp),
-                                                     new Merger<>(a, w, l,   q,
-                                                                  l+q, h-q, l, g, null, cmp));
-                    FJSubSorter rs = new FJSubSorter(new Sorter<>(a, w, l + h, q,   g, cmp),
-                                                     new Sorter<>(a, w, l+u, n-u, g, cmp),
-                                                     new Merger<>(a, w, l+h, q,
-                                                                  l+u, n-u, l+h, g, null, cmp));
-                    rs.fork();
-                    ls.compute();
-                    if (rs.tryUnfork()) rs.compute(); else rs.join();
-                    new Merger<>(w, a, l, h, l + h, n - h, l, g, null, cmp).compute();
-                } else {
-                    Arrays.sort(a, l, l+n, cmp);
-                }
-            }
-        }
-
-        static final class Merger<T> extends RecursiveAction {
-            static final long serialVersionUID = -2679539040379156203L;
-            final T[] a;
-            final T[] w;
-            final int lo;
-            final int ln;
-            final int ro;
-            final int rn;
-            final int wo;
-            final int gran;
-            final Merger<T> next;
-            final Comparator<? super T> cmp;
-
-            Merger(T[] a, T[] w, int lo, int ln, int ro, int rn, int wo,
-                   int gran, Merger<T> next, Comparator<? super T> cmp) {
-                this.a = a;
-                this.w = w;
-                this.lo = lo;
-                this.ln = ln;
-                this.ro = ro;
-                this.rn = rn;
-                this.wo = wo;
-                this.gran = gran;
-                this.next = next;
-                this.cmp = cmp;
-            }
-
-            public void compute() {
-                final T[] a = this.a;
-                final T[] w = this.w;
-                Merger<T> rights = null;
-                int nleft = ln;
-                int nright = rn;
-                while (nleft > gran) {
-                    int lh = nleft >>> 1;
-                    int splitIndex = lo + lh;
-                    T split = a[splitIndex];
-                    int rl = 0;
-                    int rh = nright;
-                    while (rl < rh) {
-                        int mid = (rl + rh) >>> 1;
-                        if (cmp.compare(split, a[ro+mid]) <= 0)
-                            rh = mid;
-                        else
-                            rl = mid + 1;
-                    }
-                    (rights = new Merger<>(a, w, splitIndex, nleft-lh, ro+rh,
-                                           nright-rh, wo+lh+rh, gran, rights, cmp)).fork();
-                    nleft = lh;
-                    nright = rh;
-                }
-
-                int l = lo;
-                int lFence = l + nleft;
-                int r = ro;
-                int rFence = r + nright;
-                int k = wo;
-                while (l < lFence && r < rFence) {
-                    T al = a[l];
-                    T ar = a[r];
-                    T t;
-                    if (cmp.compare(al, ar) <= 0) {
-                        ++l;
-                        t = al;
-                    } else {
-                        ++r;
-                        t = ar;
-                    }
-                    w[k++] = t;
-                }
-                while (l < lFence)
-                    w[k++] = a[l++];
-                while (r < rFence)
-                    w[k++] = a[r++];
-                while (rights != null) {
-                    if (rights.tryUnfork())
-                        rights.compute();
-                    else
-                        rights.join();
-                    rights = rights.next;
-                }
-            }
-        }
-    } // FJComparator
-
-    /** Utility class to sort half a partitioned array */
-    private static final class FJSubSorter extends RecursiveAction {
-        static final long serialVersionUID = 9159249695527935512L;
-        final RecursiveAction left;
-        final RecursiveAction right;
-        final RecursiveAction merger;
-
-        FJSubSorter(RecursiveAction left, RecursiveAction right,
-                    RecursiveAction merger) {
-            this.left = left;
-            this.right = right;
-            this.merger = merger;
-        }
-
-        public void compute() {
-            right.fork();
-            left.invoke();
-            right.join();
-            merger.invoke();
-        }
-    }
 }