1 /*
   2  * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.util;
  27 import java.io.*;
  28 import java.util.concurrent.atomic.AtomicLong;
  29 import java.util.function.DoubleConsumer;
  30 import java.util.function.IntConsumer;
  31 import java.util.function.LongConsumer;
  32 import java.util.stream.DoubleStream;
  33 import java.util.stream.IntStream;
  34 import java.util.stream.LongStream;
  35 import java.util.stream.StreamSupport;
  36 
  37 import sun.misc.Unsafe;
  38 
  39 /**
  40  * An instance of this class is used to generate a stream of
  41  * pseudorandom numbers. The class uses a 48-bit seed, which is
  42  * modified using a linear congruential formula. (See Donald Knuth,
  43  * <i>The Art of Computer Programming, Volume 2</i>, Section 3.2.1.)
  44  * <p>
  45  * If two instances of {@code Random} are created with the same
  46  * seed, and the same sequence of method calls is made for each, they
  47  * will generate and return identical sequences of numbers. In order to
  48  * guarantee this property, particular algorithms are specified for the
  49  * class {@code Random}. Java implementations must use all the algorithms
  50  * shown here for the class {@code Random}, for the sake of absolute
  51  * portability of Java code. However, subclasses of class {@code Random}
  52  * are permitted to use other algorithms, so long as they adhere to the
  53  * general contracts for all the methods.
  54  * <p>
  55  * The algorithms implemented by class {@code Random} use a
  56  * {@code protected} utility method that on each invocation can supply
  57  * up to 32 pseudorandomly generated bits.
  58  * <p>
  59  * Many applications will find the method {@link Math#random} simpler to use.
  60  *
  61  * <p>Instances of {@code java.util.Random} are threadsafe.
  62  * However, the concurrent use of the same {@code java.util.Random}
  63  * instance across threads may encounter contention and consequent
  64  * poor performance. Consider instead using
  65  * {@link java.util.concurrent.ThreadLocalRandom} in multithreaded
  66  * designs.
  67  *
  68  * <p>Instances of {@code java.util.Random} are not cryptographically
  69  * secure.  Consider instead using {@link java.security.SecureRandom} to
  70  * get a cryptographically secure pseudo-random number generator for use
  71  * by security-sensitive applications.
  72  *
  73  * @author  Frank Yellin
  74  * @since   1.0
  75  */
  76 public
  77 class Random implements java.io.Serializable {
  78     /** use serialVersionUID from JDK 1.1 for interoperability */
  79     static final long serialVersionUID = 3905348978240129619L;
  80 
  81     /**
  82      * The internal state associated with this pseudorandom number generator.
  83      * (The specs for the methods in this class describe the ongoing
  84      * computation of this value.)
  85      */
  86     private final AtomicLong seed;
  87 
  88     private static final long multiplier = 0x5DEECE66DL;
  89     private static final long addend = 0xBL;
  90     private static final long mask = (1L << 48) - 1;
  91 
  92     private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53)
  93 
  94     // IllegalArgumentException messages
  95     static final String BadBound = "bound must be positive";
  96     static final String BadRange = "bound must be greater than origin";
  97     static final String BadSize  = "size must be non-negative";
  98 
  99     /**
 100      * Creates a new random number generator. This constructor sets
 101      * the seed of the random number generator to a value very likely
 102      * to be distinct from any other invocation of this constructor.
 103      */
 104     public Random() {
 105         this(seedUniquifier() ^ System.nanoTime());
 106     }
 107 
 108     private static long seedUniquifier() {
 109         // L'Ecuyer, "Tables of Linear Congruential Generators of
 110         // Different Sizes and Good Lattice Structure", 1999
 111         for (;;) {
 112             long current = seedUniquifier.get();
 113             long next = current * 181783497276652981L;
 114             if (seedUniquifier.compareAndSet(current, next))
 115                 return next;
 116         }
 117     }
 118 
 119     private static final AtomicLong seedUniquifier
 120         = new AtomicLong(8682522807148012L);
 121 
 122     /**
 123      * Creates a new random number generator using a single {@code long} seed.
 124      * The seed is the initial value of the internal state of the pseudorandom
 125      * number generator which is maintained by method {@link #next}.
 126      *
 127      * <p>The invocation {@code new Random(seed)} is equivalent to:
 128      *  <pre> {@code
 129      * Random rnd = new Random();
 130      * rnd.setSeed(seed);}</pre>
 131      *
 132      * @param seed the initial seed
 133      * @see   #setSeed(long)
 134      */
 135     public Random(long seed) {
 136         if (getClass() == Random.class)
 137             this.seed = new AtomicLong(initialScramble(seed));
 138         else {
 139             // subclass might have overriden setSeed
 140             this.seed = new AtomicLong();
 141             setSeed(seed);
 142         }
 143     }
 144 
 145     private static long initialScramble(long seed) {
 146         return (seed ^ multiplier) & mask;
 147     }
 148 
 149     /**
 150      * Sets the seed of this random number generator using a single
 151      * {@code long} seed. The general contract of {@code setSeed} is
 152      * that it alters the state of this random number generator object
 153      * so as to be in exactly the same state as if it had just been
 154      * created with the argument {@code seed} as a seed. The method
 155      * {@code setSeed} is implemented by class {@code Random} by
 156      * atomically updating the seed to
 157      *  <pre>{@code (seed ^ 0x5DEECE66DL) & ((1L << 48) - 1)}</pre>
 158      * and clearing the {@code haveNextNextGaussian} flag used by {@link
 159      * #nextGaussian}.
 160      *
 161      * <p>The implementation of {@code setSeed} by class {@code Random}
 162      * happens to use only 48 bits of the given seed. In general, however,
 163      * an overriding method may use all 64 bits of the {@code long}
 164      * argument as a seed value.
 165      *
 166      * @param seed the initial seed
 167      */
 168     public synchronized void setSeed(long seed) {
 169         this.seed.set(initialScramble(seed));
 170         haveNextNextGaussian = false;
 171     }
 172 
 173     /**
 174      * Generates the next pseudorandom number. Subclasses should
 175      * override this, as this is used by all other methods.
 176      *
 177      * <p>The general contract of {@code next} is that it returns an
 178      * {@code int} value and if the argument {@code bits} is between
 179      * {@code 1} and {@code 32} (inclusive), then that many low-order
 180      * bits of the returned value will be (approximately) independently
 181      * chosen bit values, each of which is (approximately) equally
 182      * likely to be {@code 0} or {@code 1}. The method {@code next} is
 183      * implemented by class {@code Random} by atomically updating the seed to
 184      *  <pre>{@code (seed * 0x5DEECE66DL + 0xBL) & ((1L << 48) - 1)}</pre>
 185      * and returning
 186      *  <pre>{@code (int)(seed >>> (48 - bits))}.</pre>
 187      *
 188      * This is a linear congruential pseudorandom number generator, as
 189      * defined by D. H. Lehmer and described by Donald E. Knuth in
 190      * <i>The Art of Computer Programming,</i> Volume 3:
 191      * <i>Seminumerical Algorithms</i>, section 3.2.1.
 192      *
 193      * @param  bits random bits
 194      * @return the next pseudorandom value from this random number
 195      *         generator's sequence
 196      * @since  1.1
 197      */
 198     protected int next(int bits) {
 199         long oldseed, nextseed;
 200         AtomicLong seed = this.seed;
 201         do {
 202             oldseed = seed.get();
 203             nextseed = (oldseed * multiplier + addend) & mask;
 204         } while (!seed.compareAndSet(oldseed, nextseed));
 205         return (int)(nextseed >>> (48 - bits));
 206     }
 207 
 208     /**
 209      * Generates random bytes and places them into a user-supplied
 210      * byte array.  The number of random bytes produced is equal to
 211      * the length of the byte array.
 212      *
 213      * <p>The method {@code nextBytes} is implemented by class {@code Random}
 214      * as if by:
 215      *  <pre> {@code
 216      * public void nextBytes(byte[] bytes) {
 217      *   for (int i = 0; i < bytes.length; )
 218      *     for (int rnd = nextInt(), n = Math.min(bytes.length - i, 4);
 219      *          n-- > 0; rnd >>= 8)
 220      *       bytes[i++] = (byte)rnd;
 221      * }}</pre>
 222      *
 223      * @param  bytes the byte array to fill with random bytes
 224      * @throws NullPointerException if the byte array is null
 225      * @since  1.1
 226      */
 227     public void nextBytes(byte[] bytes) {
 228         for (int i = 0, len = bytes.length; i < len; )
 229             for (int rnd = nextInt(),
 230                      n = Math.min(len - i, Integer.SIZE/Byte.SIZE);
 231                  n-- > 0; rnd >>= Byte.SIZE)
 232                 bytes[i++] = (byte)rnd;
 233     }
 234 
 235     /**
 236      * The form of nextLong used by LongStream Spliterators.  If
 237      * origin is greater than bound, acts as unbounded form of
 238      * nextLong, else as bounded form.
 239      *
 240      * @param origin the least value, unless greater than bound
 241      * @param bound the upper bound (exclusive), must not equal origin
 242      * @return a pseudorandom value
 243      */
 244     final long internalNextLong(long origin, long bound) {
 245         long r = nextLong();
 246         if (origin < bound) {
 247             long n = bound - origin, m = n - 1;
 248             if ((n & m) == 0L)  // power of two
 249                 r = (r & m) + origin;
 250             else if (n > 0L) {  // reject over-represented candidates
 251                 for (long u = r >>> 1;            // ensure nonnegative
 252                      u + m - (r = u % n) < 0L;    // rejection check
 253                      u = nextLong() >>> 1) // retry
 254                     ;
 255                 r += origin;
 256             }
 257             else {              // range not representable as long
 258                 while (r < origin || r >= bound)
 259                     r = nextLong();
 260             }
 261         }
 262         return r;
 263     }
 264 
 265     /**
 266      * The form of nextInt used by IntStream Spliterators.
 267      * For the unbounded case: uses nextInt().
 268      * For the bounded case with representable range: uses nextInt(int bound)
 269      * For the bounded case with unrepresentable range: uses nextInt()
 270      *
 271      * @param origin the least value, unless greater than bound
 272      * @param bound the upper bound (exclusive), must not equal origin
 273      * @return a pseudorandom value
 274      */
 275     final int internalNextInt(int origin, int bound) {
 276         if (origin < bound) {
 277             int n = bound - origin;
 278             if (n > 0) {
 279                 return nextInt(n) + origin;
 280             }
 281             else {  // range not representable as int
 282                 int r;
 283                 do {
 284                     r = nextInt();
 285                 } while (r < origin || r >= bound);
 286                 return r;
 287             }
 288         }
 289         else {
 290             return nextInt();
 291         }
 292     }
 293 
 294     /**
 295      * The form of nextDouble used by DoubleStream Spliterators.
 296      *
 297      * @param origin the least value, unless greater than bound
 298      * @param bound the upper bound (exclusive), must not equal origin
 299      * @return a pseudorandom value
 300      */
 301     final double internalNextDouble(double origin, double bound) {
 302         double r = nextDouble();
 303         if (origin < bound) {
 304             r = r * (bound - origin) + origin;
 305             if (r >= bound) // correct for rounding
 306                 r = Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
 307         }
 308         return r;
 309     }
 310 
 311     /**
 312      * Returns the next pseudorandom, uniformly distributed {@code int}
 313      * value from this random number generator's sequence. The general
 314      * contract of {@code nextInt} is that one {@code int} value is
 315      * pseudorandomly generated and returned. All 2<sup>32</sup> possible
 316      * {@code int} values are produced with (approximately) equal probability.
 317      *
 318      * <p>The method {@code nextInt} is implemented by class {@code Random}
 319      * as if by:
 320      *  <pre> {@code
 321      * public int nextInt() {
 322      *   return next(32);
 323      * }}</pre>
 324      *
 325      * @return the next pseudorandom, uniformly distributed {@code int}
 326      *         value from this random number generator's sequence
 327      */
 328     public int nextInt() {
 329         return next(32);
 330     }
 331 
 332     /**
 333      * Returns a pseudorandom, uniformly distributed {@code int} value
 334      * between 0 (inclusive) and the specified value (exclusive), drawn from
 335      * this random number generator's sequence.  The general contract of
 336      * {@code nextInt} is that one {@code int} value in the specified range
 337      * is pseudorandomly generated and returned.  All {@code bound} possible
 338      * {@code int} values are produced with (approximately) equal
 339      * probability.  The method {@code nextInt(int bound)} is implemented by
 340      * class {@code Random} as if by:
 341      *  <pre> {@code
 342      * public int nextInt(int bound) {
 343      *   if (bound <= 0)
 344      *     throw new IllegalArgumentException("bound must be positive");
 345      *
 346      *   if ((bound & -bound) == bound)  // i.e., bound is a power of 2
 347      *     return (int)((bound * (long)next(31)) >> 31);
 348      *
 349      *   int bits, val;
 350      *   do {
 351      *       bits = next(31);
 352      *       val = bits % bound;
 353      *   } while (bits - val + (bound-1) < 0);
 354      *   return val;
 355      * }}</pre>
 356      *
 357      * <p>The hedge "approximately" is used in the foregoing description only
 358      * because the next method is only approximately an unbiased source of
 359      * independently chosen bits.  If it were a perfect source of randomly
 360      * chosen bits, then the algorithm shown would choose {@code int}
 361      * values from the stated range with perfect uniformity.
 362      * <p>
 363      * The algorithm is slightly tricky.  It rejects values that would result
 364      * in an uneven distribution (due to the fact that 2^31 is not divisible
 365      * by n). The probability of a value being rejected depends on n.  The
 366      * worst case is n=2^30+1, for which the probability of a reject is 1/2,
 367      * and the expected number of iterations before the loop terminates is 2.
 368      * <p>
 369      * The algorithm treats the case where n is a power of two specially: it
 370      * returns the correct number of high-order bits from the underlying
 371      * pseudo-random number generator.  In the absence of special treatment,
 372      * the correct number of <i>low-order</i> bits would be returned.  Linear
 373      * congruential pseudo-random number generators such as the one
 374      * implemented by this class are known to have short periods in the
 375      * sequence of values of their low-order bits.  Thus, this special case
 376      * greatly increases the length of the sequence of values returned by
 377      * successive calls to this method if n is a small power of two.
 378      *
 379      * @param bound the upper bound (exclusive).  Must be positive.
 380      * @return the next pseudorandom, uniformly distributed {@code int}
 381      *         value between zero (inclusive) and {@code bound} (exclusive)
 382      *         from this random number generator's sequence
 383      * @throws IllegalArgumentException if bound is not positive
 384      * @since 1.2
 385      */
 386     public int nextInt(int bound) {
 387         if (bound <= 0)
 388             throw new IllegalArgumentException(BadBound);
 389 
 390         int r = next(31);
 391         int m = bound - 1;
 392         if ((bound & m) == 0)  // i.e., bound is a power of 2
 393             r = (int)((bound * (long)r) >> 31);
 394         else {
 395             for (int u = r;
 396                  u - (r = u % bound) + m < 0;
 397                  u = next(31))
 398                 ;
 399         }
 400         return r;
 401     }
 402 
 403     /**
 404      * Returns the next pseudorandom, uniformly distributed {@code long}
 405      * value from this random number generator's sequence. The general
 406      * contract of {@code nextLong} is that one {@code long} value is
 407      * pseudorandomly generated and returned.
 408      *
 409      * <p>The method {@code nextLong} is implemented by class {@code Random}
 410      * as if by:
 411      *  <pre> {@code
 412      * public long nextLong() {
 413      *   return ((long)next(32) << 32) + next(32);
 414      * }}</pre>
 415      *
 416      * Because class {@code Random} uses a seed with only 48 bits,
 417      * this algorithm will not return all possible {@code long} values.
 418      *
 419      * @return the next pseudorandom, uniformly distributed {@code long}
 420      *         value from this random number generator's sequence
 421      */
 422     public long nextLong() {
 423         // it's okay that the bottom word remains signed.
 424         return ((long)(next(32)) << 32) + next(32);
 425     }
 426 
 427     /**
 428      * Returns the next pseudorandom, uniformly distributed
 429      * {@code boolean} value from this random number generator's
 430      * sequence. The general contract of {@code nextBoolean} is that one
 431      * {@code boolean} value is pseudorandomly generated and returned.  The
 432      * values {@code true} and {@code false} are produced with
 433      * (approximately) equal probability.
 434      *
 435      * <p>The method {@code nextBoolean} is implemented by class {@code Random}
 436      * as if by:
 437      *  <pre> {@code
 438      * public boolean nextBoolean() {
 439      *   return next(1) != 0;
 440      * }}</pre>
 441      *
 442      * @return the next pseudorandom, uniformly distributed
 443      *         {@code boolean} value from this random number generator's
 444      *         sequence
 445      * @since 1.2
 446      */
 447     public boolean nextBoolean() {
 448         return next(1) != 0;
 449     }
 450 
 451     /**
 452      * Returns the next pseudorandom, uniformly distributed {@code float}
 453      * value between {@code 0.0} and {@code 1.0} from this random
 454      * number generator's sequence.
 455      *
 456      * <p>The general contract of {@code nextFloat} is that one
 457      * {@code float} value, chosen (approximately) uniformly from the
 458      * range {@code 0.0f} (inclusive) to {@code 1.0f} (exclusive), is
 459      * pseudorandomly generated and returned. All 2<sup>24</sup> possible
 460      * {@code float} values of the form <i>m&nbsp;x&nbsp;</i>2<sup>-24</sup>,
 461      * where <i>m</i> is a positive integer less than 2<sup>24</sup>, are
 462      * produced with (approximately) equal probability.
 463      *
 464      * <p>The method {@code nextFloat} is implemented by class {@code Random}
 465      * as if by:
 466      *  <pre> {@code
 467      * public float nextFloat() {
 468      *   return next(24) / ((float)(1 << 24));
 469      * }}</pre>
 470      *
 471      * <p>The hedge "approximately" is used in the foregoing description only
 472      * because the next method is only approximately an unbiased source of
 473      * independently chosen bits. If it were a perfect source of randomly
 474      * chosen bits, then the algorithm shown would choose {@code float}
 475      * values from the stated range with perfect uniformity.<p>
 476      * [In early versions of Java, the result was incorrectly calculated as:
 477      *  <pre> {@code
 478      *   return next(30) / ((float)(1 << 30));}</pre>
 479      * This might seem to be equivalent, if not better, but in fact it
 480      * introduced a slight nonuniformity because of the bias in the rounding
 481      * of floating-point numbers: it was slightly more likely that the
 482      * low-order bit of the significand would be 0 than that it would be 1.]
 483      *
 484      * @return the next pseudorandom, uniformly distributed {@code float}
 485      *         value between {@code 0.0} and {@code 1.0} from this
 486      *         random number generator's sequence
 487      */
 488     public float nextFloat() {
 489         return next(24) / ((float)(1 << 24));
 490     }
 491 
 492     /**
 493      * Returns the next pseudorandom, uniformly distributed
 494      * {@code double} value between {@code 0.0} and
 495      * {@code 1.0} from this random number generator's sequence.
 496      *
 497      * <p>The general contract of {@code nextDouble} is that one
 498      * {@code double} value, chosen (approximately) uniformly from the
 499      * range {@code 0.0d} (inclusive) to {@code 1.0d} (exclusive), is
 500      * pseudorandomly generated and returned.
 501      *
 502      * <p>The method {@code nextDouble} is implemented by class {@code Random}
 503      * as if by:
 504      *  <pre> {@code
 505      * public double nextDouble() {
 506      *   return (((long)next(26) << 27) + next(27))
 507      *     / (double)(1L << 53);
 508      * }}</pre>
 509      *
 510      * <p>The hedge "approximately" is used in the foregoing description only
 511      * because the {@code next} method is only approximately an unbiased
 512      * source of independently chosen bits. If it were a perfect source of
 513      * randomly chosen bits, then the algorithm shown would choose
 514      * {@code double} values from the stated range with perfect uniformity.
 515      * <p>[In early versions of Java, the result was incorrectly calculated as:
 516      *  <pre> {@code
 517      *   return (((long)next(27) << 27) + next(27))
 518      *     / (double)(1L << 54);}</pre>
 519      * This might seem to be equivalent, if not better, but in fact it
 520      * introduced a large nonuniformity because of the bias in the rounding
 521      * of floating-point numbers: it was three times as likely that the
 522      * low-order bit of the significand would be 0 than that it would be 1!
 523      * This nonuniformity probably doesn't matter much in practice, but we
 524      * strive for perfection.]
 525      *
 526      * @return the next pseudorandom, uniformly distributed {@code double}
 527      *         value between {@code 0.0} and {@code 1.0} from this
 528      *         random number generator's sequence
 529      * @see Math#random
 530      */
 531     public double nextDouble() {
 532         return (((long)(next(26)) << 27) + next(27)) * DOUBLE_UNIT;
 533     }
 534 
 535     private double nextNextGaussian;
 536     private boolean haveNextNextGaussian = false;
 537 
 538     /**
 539      * Returns the next pseudorandom, Gaussian ("normally") distributed
 540      * {@code double} value with mean {@code 0.0} and standard
 541      * deviation {@code 1.0} from this random number generator's sequence.
 542      * <p>
 543      * The general contract of {@code nextGaussian} is that one
 544      * {@code double} value, chosen from (approximately) the usual
 545      * normal distribution with mean {@code 0.0} and standard deviation
 546      * {@code 1.0}, is pseudorandomly generated and returned.
 547      *
 548      * <p>The method {@code nextGaussian} is implemented by class
 549      * {@code Random} as if by a threadsafe version of the following:
 550      *  <pre> {@code
 551      * private double nextNextGaussian;
 552      * private boolean haveNextNextGaussian = false;
 553      *
 554      * public double nextGaussian() {
 555      *   if (haveNextNextGaussian) {
 556      *     haveNextNextGaussian = false;
 557      *     return nextNextGaussian;
 558      *   } else {
 559      *     double v1, v2, s;
 560      *     do {
 561      *       v1 = 2 * nextDouble() - 1;   // between -1.0 and 1.0
 562      *       v2 = 2 * nextDouble() - 1;   // between -1.0 and 1.0
 563      *       s = v1 * v1 + v2 * v2;
 564      *     } while (s >= 1 || s == 0);
 565      *     double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s);
 566      *     nextNextGaussian = v2 * multiplier;
 567      *     haveNextNextGaussian = true;
 568      *     return v1 * multiplier;
 569      *   }
 570      * }}</pre>
 571      * This uses the <i>polar method</i> of G. E. P. Box, M. E. Muller, and
 572      * G. Marsaglia, as described by Donald E. Knuth in <i>The Art of
 573      * Computer Programming</i>, Volume 3: <i>Seminumerical Algorithms</i>,
 574      * section 3.4.1, subsection C, algorithm P. Note that it generates two
 575      * independent values at the cost of only one call to {@code StrictMath.log}
 576      * and one call to {@code StrictMath.sqrt}.
 577      *
 578      * @return the next pseudorandom, Gaussian ("normally") distributed
 579      *         {@code double} value with mean {@code 0.0} and
 580      *         standard deviation {@code 1.0} from this random number
 581      *         generator's sequence
 582      */
 583     public synchronized double nextGaussian() {
 584         // See Knuth, ACP, Section 3.4.1 Algorithm C.
 585         if (haveNextNextGaussian) {
 586             haveNextNextGaussian = false;
 587             return nextNextGaussian;
 588         } else {
 589             double v1, v2, s;
 590             do {
 591                 v1 = 2 * nextDouble() - 1; // between -1 and 1
 592                 v2 = 2 * nextDouble() - 1; // between -1 and 1
 593                 s = v1 * v1 + v2 * v2;
 594             } while (s >= 1 || s == 0);
 595             double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s);
 596             nextNextGaussian = v2 * multiplier;
 597             haveNextNextGaussian = true;
 598             return v1 * multiplier;
 599         }
 600     }
 601 
 602     // stream methods, coded in a way intended to better isolate for
 603     // maintenance purposes the small differences across forms.
 604 
 605     /**
 606      * Returns a stream producing the given {@code streamSize} number of
 607      * pseudorandom {@code int} values.
 608      *
 609      * <p>A pseudorandom {@code int} value is generated as if it's the result of
 610      * calling the method {@link #nextInt()}.
 611      *
 612      * @param streamSize the number of values to generate
 613      * @return a stream of pseudorandom {@code int} values
 614      * @throws IllegalArgumentException if {@code streamSize} is
 615      *         less than zero
 616      * @since 1.8
 617      */
 618     public IntStream ints(long streamSize) {
 619         if (streamSize < 0L)
 620             throw new IllegalArgumentException(BadSize);
 621         return StreamSupport.intStream
 622                 (new RandomIntsSpliterator
 623                          (this, 0L, streamSize, Integer.MAX_VALUE, 0),
 624                  false);
 625     }
 626 
 627     /**
 628      * Returns an effectively unlimited stream of pseudorandom {@code int}
 629      * values.
 630      *
 631      * <p>A pseudorandom {@code int} value is generated as if it's the result of
 632      * calling the method {@link #nextInt()}.
 633      *
 634      * @implNote This method is implemented to be equivalent to {@code
 635      * ints(Long.MAX_VALUE)}.
 636      *
 637      * @return a stream of pseudorandom {@code int} values
 638      * @since 1.8
 639      */
 640     public IntStream ints() {
 641         return StreamSupport.intStream
 642                 (new RandomIntsSpliterator
 643                          (this, 0L, Long.MAX_VALUE, Integer.MAX_VALUE, 0),
 644                  false);
 645     }
 646 
 647     /**
 648      * Returns a stream producing the given {@code streamSize} number
 649      * of pseudorandom {@code int} values, each conforming to the given
 650      * origin (inclusive) and bound (exclusive).
 651      *
 652      * <p>A pseudorandom {@code int} value is generated as if it's the result of
 653      * calling the following method with the origin and bound:
 654      * <pre> {@code
 655      * int nextInt(int origin, int bound) {
 656      *   int n = bound - origin;
 657      *   if (n > 0) {
 658      *     return nextInt(n) + origin;
 659      *   }
 660      *   else {  // range not representable as int
 661      *     int r;
 662      *     do {
 663      *       r = nextInt();
 664      *     } while (r < origin || r >= bound);
 665      *     return r;
 666      *   }
 667      * }}</pre>
 668      *
 669      * @param streamSize the number of values to generate
 670      * @param randomNumberOrigin the origin (inclusive) of each random value
 671      * @param randomNumberBound the bound (exclusive) of each random value
 672      * @return a stream of pseudorandom {@code int} values,
 673      *         each with the given origin (inclusive) and bound (exclusive)
 674      * @throws IllegalArgumentException if {@code streamSize} is
 675      *         less than zero, or {@code randomNumberOrigin}
 676      *         is greater than or equal to {@code randomNumberBound}
 677      * @since 1.8
 678      */
 679     public IntStream ints(long streamSize, int randomNumberOrigin,
 680                           int randomNumberBound) {
 681         if (streamSize < 0L)
 682             throw new IllegalArgumentException(BadSize);
 683         if (randomNumberOrigin >= randomNumberBound)
 684             throw new IllegalArgumentException(BadRange);
 685         return StreamSupport.intStream
 686                 (new RandomIntsSpliterator
 687                          (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
 688                  false);
 689     }
 690 
 691     /**
 692      * Returns an effectively unlimited stream of pseudorandom {@code
 693      * int} values, each conforming to the given origin (inclusive) and bound
 694      * (exclusive).
 695      *
 696      * <p>A pseudorandom {@code int} value is generated as if it's the result of
 697      * calling the following method with the origin and bound:
 698      * <pre> {@code
 699      * int nextInt(int origin, int bound) {
 700      *   int n = bound - origin;
 701      *   if (n > 0) {
 702      *     return nextInt(n) + origin;
 703      *   }
 704      *   else {  // range not representable as int
 705      *     int r;
 706      *     do {
 707      *       r = nextInt();
 708      *     } while (r < origin || r >= bound);
 709      *     return r;
 710      *   }
 711      * }}</pre>
 712      *
 713      * @implNote This method is implemented to be equivalent to {@code
 714      * ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
 715      *
 716      * @param randomNumberOrigin the origin (inclusive) of each random value
 717      * @param randomNumberBound the bound (exclusive) of each random value
 718      * @return a stream of pseudorandom {@code int} values,
 719      *         each with the given origin (inclusive) and bound (exclusive)
 720      * @throws IllegalArgumentException if {@code randomNumberOrigin}
 721      *         is greater than or equal to {@code randomNumberBound}
 722      * @since 1.8
 723      */
 724     public IntStream ints(int randomNumberOrigin, int randomNumberBound) {
 725         if (randomNumberOrigin >= randomNumberBound)
 726             throw new IllegalArgumentException(BadRange);
 727         return StreamSupport.intStream
 728                 (new RandomIntsSpliterator
 729                          (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
 730                  false);
 731     }
 732 
 733     /**
 734      * Returns a stream producing the given {@code streamSize} number of
 735      * pseudorandom {@code long} values.
 736      *
 737      * <p>A pseudorandom {@code long} value is generated as if it's the result
 738      * of calling the method {@link #nextLong()}.
 739      *
 740      * @param streamSize the number of values to generate
 741      * @return a stream of pseudorandom {@code long} values
 742      * @throws IllegalArgumentException if {@code streamSize} is
 743      *         less than zero
 744      * @since 1.8
 745      */
 746     public LongStream longs(long streamSize) {
 747         if (streamSize < 0L)
 748             throw new IllegalArgumentException(BadSize);
 749         return StreamSupport.longStream
 750                 (new RandomLongsSpliterator
 751                          (this, 0L, streamSize, Long.MAX_VALUE, 0L),
 752                  false);
 753     }
 754 
 755     /**
 756      * Returns an effectively unlimited stream of pseudorandom {@code long}
 757      * values.
 758      *
 759      * <p>A pseudorandom {@code long} value is generated as if it's the result
 760      * of calling the method {@link #nextLong()}.
 761      *
 762      * @implNote This method is implemented to be equivalent to {@code
 763      * longs(Long.MAX_VALUE)}.
 764      *
 765      * @return a stream of pseudorandom {@code long} values
 766      * @since 1.8
 767      */
 768     public LongStream longs() {
 769         return StreamSupport.longStream
 770                 (new RandomLongsSpliterator
 771                          (this, 0L, Long.MAX_VALUE, Long.MAX_VALUE, 0L),
 772                  false);
 773     }
 774 
 775     /**
 776      * Returns a stream producing the given {@code streamSize} number of
 777      * pseudorandom {@code long}, each conforming to the given origin
 778      * (inclusive) and bound (exclusive).
 779      *
 780      * <p>A pseudorandom {@code long} value is generated as if it's the result
 781      * of calling the following method with the origin and bound:
 782      * <pre> {@code
 783      * long nextLong(long origin, long bound) {
 784      *   long r = nextLong();
 785      *   long n = bound - origin, m = n - 1;
 786      *   if ((n & m) == 0L)  // power of two
 787      *     r = (r & m) + origin;
 788      *   else if (n > 0L) {  // reject over-represented candidates
 789      *     for (long u = r >>> 1;            // ensure nonnegative
 790      *          u + m - (r = u % n) < 0L;    // rejection check
 791      *          u = nextLong() >>> 1) // retry
 792      *         ;
 793      *     r += origin;
 794      *   }
 795      *   else {              // range not representable as long
 796      *     while (r < origin || r >= bound)
 797      *       r = nextLong();
 798      *   }
 799      *   return r;
 800      * }}</pre>
 801      *
 802      * @param streamSize the number of values to generate
 803      * @param randomNumberOrigin the origin (inclusive) of each random value
 804      * @param randomNumberBound the bound (exclusive) of each random value
 805      * @return a stream of pseudorandom {@code long} values,
 806      *         each with the given origin (inclusive) and bound (exclusive)
 807      * @throws IllegalArgumentException if {@code streamSize} is
 808      *         less than zero, or {@code randomNumberOrigin}
 809      *         is greater than or equal to {@code randomNumberBound}
 810      * @since 1.8
 811      */
 812     public LongStream longs(long streamSize, long randomNumberOrigin,
 813                             long randomNumberBound) {
 814         if (streamSize < 0L)
 815             throw new IllegalArgumentException(BadSize);
 816         if (randomNumberOrigin >= randomNumberBound)
 817             throw new IllegalArgumentException(BadRange);
 818         return StreamSupport.longStream
 819                 (new RandomLongsSpliterator
 820                          (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
 821                  false);
 822     }
 823 
 824     /**
 825      * Returns an effectively unlimited stream of pseudorandom {@code
 826      * long} values, each conforming to the given origin (inclusive) and bound
 827      * (exclusive).
 828      *
 829      * <p>A pseudorandom {@code long} value is generated as if it's the result
 830      * of calling the following method with the origin and bound:
 831      * <pre> {@code
 832      * long nextLong(long origin, long bound) {
 833      *   long r = nextLong();
 834      *   long n = bound - origin, m = n - 1;
 835      *   if ((n & m) == 0L)  // power of two
 836      *     r = (r & m) + origin;
 837      *   else if (n > 0L) {  // reject over-represented candidates
 838      *     for (long u = r >>> 1;            // ensure nonnegative
 839      *          u + m - (r = u % n) < 0L;    // rejection check
 840      *          u = nextLong() >>> 1) // retry
 841      *         ;
 842      *     r += origin;
 843      *   }
 844      *   else {              // range not representable as long
 845      *     while (r < origin || r >= bound)
 846      *       r = nextLong();
 847      *   }
 848      *   return r;
 849      * }}</pre>
 850      *
 851      * @implNote This method is implemented to be equivalent to {@code
 852      * longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
 853      *
 854      * @param randomNumberOrigin the origin (inclusive) of each random value
 855      * @param randomNumberBound the bound (exclusive) of each random value
 856      * @return a stream of pseudorandom {@code long} values,
 857      *         each with the given origin (inclusive) and bound (exclusive)
 858      * @throws IllegalArgumentException if {@code randomNumberOrigin}
 859      *         is greater than or equal to {@code randomNumberBound}
 860      * @since 1.8
 861      */
 862     public LongStream longs(long randomNumberOrigin, long randomNumberBound) {
 863         if (randomNumberOrigin >= randomNumberBound)
 864             throw new IllegalArgumentException(BadRange);
 865         return StreamSupport.longStream
 866                 (new RandomLongsSpliterator
 867                          (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
 868                  false);
 869     }
 870 
 871     /**
 872      * Returns a stream producing the given {@code streamSize} number of
 873      * pseudorandom {@code double} values, each between zero
 874      * (inclusive) and one (exclusive).
 875      *
 876      * <p>A pseudorandom {@code double} value is generated as if it's the result
 877      * of calling the method {@link #nextDouble()}.
 878      *
 879      * @param streamSize the number of values to generate
 880      * @return a stream of {@code double} values
 881      * @throws IllegalArgumentException if {@code streamSize} is
 882      *         less than zero
 883      * @since 1.8
 884      */
 885     public DoubleStream doubles(long streamSize) {
 886         if (streamSize < 0L)
 887             throw new IllegalArgumentException(BadSize);
 888         return StreamSupport.doubleStream
 889                 (new RandomDoublesSpliterator
 890                          (this, 0L, streamSize, Double.MAX_VALUE, 0.0),
 891                  false);
 892     }
 893 
 894     /**
 895      * Returns an effectively unlimited stream of pseudorandom {@code
 896      * double} values, each between zero (inclusive) and one
 897      * (exclusive).
 898      *
 899      * <p>A pseudorandom {@code double} value is generated as if it's the result
 900      * of calling the method {@link #nextDouble()}.
 901      *
 902      * @implNote This method is implemented to be equivalent to {@code
 903      * doubles(Long.MAX_VALUE)}.
 904      *
 905      * @return a stream of pseudorandom {@code double} values
 906      * @since 1.8
 907      */
 908     public DoubleStream doubles() {
 909         return StreamSupport.doubleStream
 910                 (new RandomDoublesSpliterator
 911                          (this, 0L, Long.MAX_VALUE, Double.MAX_VALUE, 0.0),
 912                  false);
 913     }
 914 
 915     /**
 916      * Returns a stream producing the given {@code streamSize} number of
 917      * pseudorandom {@code double} values, each conforming to the given origin
 918      * (inclusive) and bound (exclusive).
 919      *
 920      * <p>A pseudorandom {@code double} value is generated as if it's the result
 921      * of calling the following method with the origin and bound:
 922      * <pre> {@code
 923      * double nextDouble(double origin, double bound) {
 924      *   double r = nextDouble();
 925      *   r = r * (bound - origin) + origin;
 926      *   if (r >= bound) // correct for rounding
 927      *     r = Math.nextDown(bound);
 928      *   return r;
 929      * }}</pre>
 930      *
 931      * @param streamSize the number of values to generate
 932      * @param randomNumberOrigin the origin (inclusive) of each random value
 933      * @param randomNumberBound the bound (exclusive) of each random value
 934      * @return a stream of pseudorandom {@code double} values,
 935      *         each with the given origin (inclusive) and bound (exclusive)
 936      * @throws IllegalArgumentException if {@code streamSize} is
 937      *         less than zero
 938      * @throws IllegalArgumentException if {@code randomNumberOrigin}
 939      *         is greater than or equal to {@code randomNumberBound}
 940      * @since 1.8
 941      */
 942     public DoubleStream doubles(long streamSize, double randomNumberOrigin,
 943                                 double randomNumberBound) {
 944         if (streamSize < 0L)
 945             throw new IllegalArgumentException(BadSize);
 946         if (!(randomNumberOrigin < randomNumberBound))
 947             throw new IllegalArgumentException(BadRange);
 948         return StreamSupport.doubleStream
 949                 (new RandomDoublesSpliterator
 950                          (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
 951                  false);
 952     }
 953 
 954     /**
 955      * Returns an effectively unlimited stream of pseudorandom {@code
 956      * double} values, each conforming to the given origin (inclusive) and bound
 957      * (exclusive).
 958      *
 959      * <p>A pseudorandom {@code double} value is generated as if it's the result
 960      * of calling the following method with the origin and bound:
 961      * <pre> {@code
 962      * double nextDouble(double origin, double bound) {
 963      *   double r = nextDouble();
 964      *   r = r * (bound - origin) + origin;
 965      *   if (r >= bound) // correct for rounding
 966      *     r = Math.nextDown(bound);
 967      *   return r;
 968      * }}</pre>
 969      *
 970      * @implNote This method is implemented to be equivalent to {@code
 971      * doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
 972      *
 973      * @param randomNumberOrigin the origin (inclusive) of each random value
 974      * @param randomNumberBound the bound (exclusive) of each random value
 975      * @return a stream of pseudorandom {@code double} values,
 976      *         each with the given origin (inclusive) and bound (exclusive)
 977      * @throws IllegalArgumentException if {@code randomNumberOrigin}
 978      *         is greater than or equal to {@code randomNumberBound}
 979      * @since 1.8
 980      */
 981     public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
 982         if (!(randomNumberOrigin < randomNumberBound))
 983             throw new IllegalArgumentException(BadRange);
 984         return StreamSupport.doubleStream
 985                 (new RandomDoublesSpliterator
 986                          (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
 987                  false);
 988     }
 989 
 990     /**
 991      * Spliterator for int streams.  We multiplex the four int
 992      * versions into one class by treating a bound less than origin as
 993      * unbounded, and also by treating "infinite" as equivalent to
 994      * Long.MAX_VALUE. For splits, it uses the standard divide-by-two
 995      * approach. The long and double versions of this class are
 996      * identical except for types.
 997      */
 998     static final class RandomIntsSpliterator implements Spliterator.OfInt {
 999         final Random rng;
1000         long index;
1001         final long fence;
1002         final int origin;
1003         final int bound;
1004         RandomIntsSpliterator(Random rng, long index, long fence,
1005                               int origin, int bound) {
1006             this.rng = rng; this.index = index; this.fence = fence;
1007             this.origin = origin; this.bound = bound;
1008         }
1009 
1010         public RandomIntsSpliterator trySplit() {
1011             long i = index, m = (i + fence) >>> 1;
1012             return (m <= i) ? null :
1013                    new RandomIntsSpliterator(rng, i, index = m, origin, bound);
1014         }
1015 
1016         public long estimateSize() {
1017             return fence - index;
1018         }
1019 
1020         public int characteristics() {
1021             return (Spliterator.SIZED | Spliterator.SUBSIZED |
1022                     Spliterator.NONNULL | Spliterator.IMMUTABLE);
1023         }
1024 
1025         public boolean tryAdvance(IntConsumer consumer) {
1026             if (consumer == null) throw new NullPointerException();
1027             long i = index, f = fence;
1028             if (i < f) {
1029                 consumer.accept(rng.internalNextInt(origin, bound));
1030                 index = i + 1;
1031                 return true;
1032             }
1033             return false;
1034         }
1035 
1036         public void forEachRemaining(IntConsumer consumer) {
1037             if (consumer == null) throw new NullPointerException();
1038             long i = index, f = fence;
1039             if (i < f) {
1040                 index = f;
1041                 Random r = rng;
1042                 int o = origin, b = bound;
1043                 do {
1044                     consumer.accept(r.internalNextInt(o, b));
1045                 } while (++i < f);
1046             }
1047         }
1048     }
1049 
1050     /**
1051      * Spliterator for long streams.
1052      */
1053     static final class RandomLongsSpliterator implements Spliterator.OfLong {
1054         final Random rng;
1055         long index;
1056         final long fence;
1057         final long origin;
1058         final long bound;
1059         RandomLongsSpliterator(Random rng, long index, long fence,
1060                                long origin, long bound) {
1061             this.rng = rng; this.index = index; this.fence = fence;
1062             this.origin = origin; this.bound = bound;
1063         }
1064 
1065         public RandomLongsSpliterator trySplit() {
1066             long i = index, m = (i + fence) >>> 1;
1067             return (m <= i) ? null :
1068                    new RandomLongsSpliterator(rng, i, index = m, origin, bound);
1069         }
1070 
1071         public long estimateSize() {
1072             return fence - index;
1073         }
1074 
1075         public int characteristics() {
1076             return (Spliterator.SIZED | Spliterator.SUBSIZED |
1077                     Spliterator.NONNULL | Spliterator.IMMUTABLE);
1078         }
1079 
1080         public boolean tryAdvance(LongConsumer consumer) {
1081             if (consumer == null) throw new NullPointerException();
1082             long i = index, f = fence;
1083             if (i < f) {
1084                 consumer.accept(rng.internalNextLong(origin, bound));
1085                 index = i + 1;
1086                 return true;
1087             }
1088             return false;
1089         }
1090 
1091         public void forEachRemaining(LongConsumer consumer) {
1092             if (consumer == null) throw new NullPointerException();
1093             long i = index, f = fence;
1094             if (i < f) {
1095                 index = f;
1096                 Random r = rng;
1097                 long o = origin, b = bound;
1098                 do {
1099                     consumer.accept(r.internalNextLong(o, b));
1100                 } while (++i < f);
1101             }
1102         }
1103 
1104     }
1105 
1106     /**
1107      * Spliterator for double streams.
1108      */
1109     static final class RandomDoublesSpliterator implements Spliterator.OfDouble {
1110         final Random rng;
1111         long index;
1112         final long fence;
1113         final double origin;
1114         final double bound;
1115         RandomDoublesSpliterator(Random rng, long index, long fence,
1116                                  double origin, double bound) {
1117             this.rng = rng; this.index = index; this.fence = fence;
1118             this.origin = origin; this.bound = bound;
1119         }
1120 
1121         public RandomDoublesSpliterator trySplit() {
1122             long i = index, m = (i + fence) >>> 1;
1123             return (m <= i) ? null :
1124                    new RandomDoublesSpliterator(rng, i, index = m, origin, bound);
1125         }
1126 
1127         public long estimateSize() {
1128             return fence - index;
1129         }
1130 
1131         public int characteristics() {
1132             return (Spliterator.SIZED | Spliterator.SUBSIZED |
1133                     Spliterator.NONNULL | Spliterator.IMMUTABLE);
1134         }
1135 
1136         public boolean tryAdvance(DoubleConsumer consumer) {
1137             if (consumer == null) throw new NullPointerException();
1138             long i = index, f = fence;
1139             if (i < f) {
1140                 consumer.accept(rng.internalNextDouble(origin, bound));
1141                 index = i + 1;
1142                 return true;
1143             }
1144             return false;
1145         }
1146 
1147         public void forEachRemaining(DoubleConsumer consumer) {
1148             if (consumer == null) throw new NullPointerException();
1149             long i = index, f = fence;
1150             if (i < f) {
1151                 index = f;
1152                 Random r = rng;
1153                 double o = origin, b = bound;
1154                 do {
1155                     consumer.accept(r.internalNextDouble(o, b));
1156                 } while (++i < f);
1157             }
1158         }
1159     }
1160 
1161     /**
1162      * Serializable fields for Random.
1163      *
1164      * @serialField    seed long
1165      *              seed for random computations
1166      * @serialField    nextNextGaussian double
1167      *              next Gaussian to be returned
1168      * @serialField      haveNextNextGaussian boolean
1169      *              nextNextGaussian is valid
1170      */
1171     private static final ObjectStreamField[] serialPersistentFields = {
1172         new ObjectStreamField("seed", Long.TYPE),
1173         new ObjectStreamField("nextNextGaussian", Double.TYPE),
1174         new ObjectStreamField("haveNextNextGaussian", Boolean.TYPE)
1175     };
1176 
1177     /**
1178      * Reconstitute the {@code Random} instance from a stream (that is,
1179      * deserialize it).
1180      */
1181     private void readObject(java.io.ObjectInputStream s)
1182         throws java.io.IOException, ClassNotFoundException {
1183 
1184         ObjectInputStream.GetField fields = s.readFields();
1185 
1186         // The seed is read in as {@code long} for
1187         // historical reasons, but it is converted to an AtomicLong.
1188         long seedVal = fields.get("seed", -1L);
1189         if (seedVal < 0)
1190           throw new java.io.StreamCorruptedException(
1191                               "Random: invalid seed");
1192         resetSeed(seedVal);
1193         nextNextGaussian = fields.get("nextNextGaussian", 0.0);
1194         haveNextNextGaussian = fields.get("haveNextNextGaussian", false);
1195     }
1196 
1197     /**
1198      * Save the {@code Random} instance to a stream.
1199      */
1200     private synchronized void writeObject(ObjectOutputStream s)
1201         throws IOException {
1202 
1203         // set the values of the Serializable fields
1204         ObjectOutputStream.PutField fields = s.putFields();
1205 
1206         // The seed is serialized as a long for historical reasons.
1207         fields.put("seed", seed.get());
1208         fields.put("nextNextGaussian", nextNextGaussian);
1209         fields.put("haveNextNextGaussian", haveNextNextGaussian);
1210 
1211         // save them
1212         s.writeFields();
1213     }
1214 
1215     // Support for resetting seed while deserializing
1216     private static final Unsafe unsafe = Unsafe.getUnsafe();
1217     private static final long seedOffset;
1218     static {
1219         try {
1220             seedOffset = unsafe.objectFieldOffset
1221                 (Random.class.getDeclaredField("seed"));
1222         } catch (Exception ex) { throw new Error(ex); }
1223     }
1224     private void resetSeed(long seedVal) {
1225         unsafe.putObjectVolatile(this, seedOffset, new AtomicLong(seedVal));
1226     }
1227 }