1 /*
   2  * Copyright (c) 1994, 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.lang;
  27 
  28 import java.lang.annotation.Native;
  29 import java.math.*;
  30 import java.util.Objects;
  31 
  32 
  33 /**
  34  * The {@code Long} class wraps a value of the primitive type {@code
  35  * long} in an object. An object of type {@code Long} contains a
  36  * single field whose type is {@code long}.
  37  *
  38  * <p> In addition, this class provides several methods for converting
  39  * a {@code long} to a {@code String} and a {@code String} to a {@code
  40  * long}, as well as other constants and methods useful when dealing
  41  * with a {@code long}.
  42  *
  43  * <p>Implementation note: The implementations of the "bit twiddling"
  44  * methods (such as {@link #highestOneBit(long) highestOneBit} and
  45  * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
  46  * based on material from Henry S. Warren, Jr.'s <i>Hacker's
  47  * Delight</i>, (Addison Wesley, 2002).
  48  *
  49  * @author  Lee Boynton
  50  * @author  Arthur van Hoff
  51  * @author  Josh Bloch
  52  * @author  Joseph D. Darcy
  53  * @since   1.0
  54  */
  55 public final class Long extends Number implements Comparable<Long> {
  56     /**
  57      * A constant holding the minimum value a {@code long} can
  58      * have, -2<sup>63</sup>.
  59      */
  60     @Native public static final long MIN_VALUE = 0x8000000000000000L;
  61 
  62     /**
  63      * A constant holding the maximum value a {@code long} can
  64      * have, 2<sup>63</sup>-1.
  65      */
  66     @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
  67 
  68     /**
  69      * The {@code Class} instance representing the primitive type
  70      * {@code long}.
  71      *
  72      * @since   1.1
  73      */
  74     @SuppressWarnings("unchecked")
  75     public static final Class<Long>     TYPE = (Class<Long>) Class.getPrimitiveClass("long");
  76 
  77     /**
  78      * Returns a string representation of the first argument in the
  79      * radix specified by the second argument.
  80      *
  81      * <p>If the radix is smaller than {@code Character.MIN_RADIX}
  82      * or larger than {@code Character.MAX_RADIX}, then the radix
  83      * {@code 10} is used instead.
  84      *
  85      * <p>If the first argument is negative, the first element of the
  86      * result is the ASCII minus sign {@code '-'}
  87      * ({@code '\u005Cu002d'}). If the first argument is not
  88      * negative, no sign character appears in the result.
  89      *
  90      * <p>The remaining characters of the result represent the magnitude
  91      * of the first argument. If the magnitude is zero, it is
  92      * represented by a single zero character {@code '0'}
  93      * ({@code '\u005Cu0030'}); otherwise, the first character of
  94      * the representation of the magnitude will not be the zero
  95      * character.  The following ASCII characters are used as digits:
  96      *
  97      * <blockquote>
  98      *   {@code 0123456789abcdefghijklmnopqrstuvwxyz}
  99      * </blockquote>
 100      *
 101      * These are {@code '\u005Cu0030'} through
 102      * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
 103      * {@code '\u005Cu007a'}. If {@code radix} is
 104      * <var>N</var>, then the first <var>N</var> of these characters
 105      * are used as radix-<var>N</var> digits in the order shown. Thus,
 106      * the digits for hexadecimal (radix 16) are
 107      * {@code 0123456789abcdef}. If uppercase letters are
 108      * desired, the {@link java.lang.String#toUpperCase()} method may
 109      * be called on the result:
 110      *
 111      * <blockquote>
 112      *  {@code Long.toString(n, 16).toUpperCase()}
 113      * </blockquote>
 114      *
 115      * @param   i       a {@code long} to be converted to a string.
 116      * @param   radix   the radix to use in the string representation.
 117      * @return  a string representation of the argument in the specified radix.
 118      * @see     java.lang.Character#MAX_RADIX
 119      * @see     java.lang.Character#MIN_RADIX
 120      */
 121     public static String toString(long i, int radix) {
 122         if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
 123             radix = 10;
 124         if (radix == 10)
 125             return toString(i);
 126         char[] buf = new char[65];
 127         int charPos = 64;
 128         boolean negative = (i < 0);
 129 
 130         if (!negative) {
 131             i = -i;
 132         }
 133 
 134         while (i <= -radix) {
 135             buf[charPos--] = Integer.digits[(int)(-(i % radix))];
 136             i = i / radix;
 137         }
 138         buf[charPos] = Integer.digits[(int)(-i)];
 139 
 140         if (negative) {
 141             buf[--charPos] = '-';
 142         }
 143 
 144         return new String(buf, charPos, (65 - charPos));
 145     }
 146 
 147     /**
 148      * Returns a string representation of the first argument as an
 149      * unsigned integer value in the radix specified by the second
 150      * argument.
 151      *
 152      * <p>If the radix is smaller than {@code Character.MIN_RADIX}
 153      * or larger than {@code Character.MAX_RADIX}, then the radix
 154      * {@code 10} is used instead.
 155      *
 156      * <p>Note that since the first argument is treated as an unsigned
 157      * value, no leading sign character is printed.
 158      *
 159      * <p>If the magnitude is zero, it is represented by a single zero
 160      * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
 161      * the first character of the representation of the magnitude will
 162      * not be the zero character.
 163      *
 164      * <p>The behavior of radixes and the characters used as digits
 165      * are the same as {@link #toString(long, int) toString}.
 166      *
 167      * @param   i       an integer to be converted to an unsigned string.
 168      * @param   radix   the radix to use in the string representation.
 169      * @return  an unsigned string representation of the argument in the specified radix.
 170      * @see     #toString(long, int)
 171      * @since 1.8
 172      */
 173     public static String toUnsignedString(long i, int radix) {
 174         if (i >= 0)
 175             return toString(i, radix);
 176         else {
 177             switch (radix) {
 178             case 2:
 179                 return toBinaryString(i);
 180 
 181             case 4:
 182                 return toUnsignedString0(i, 2);
 183 
 184             case 8:
 185                 return toOctalString(i);
 186 
 187             case 10:
 188                 /*
 189                  * We can get the effect of an unsigned division by 10
 190                  * on a long value by first shifting right, yielding a
 191                  * positive value, and then dividing by 5.  This
 192                  * allows the last digit and preceding digits to be
 193                  * isolated more quickly than by an initial conversion
 194                  * to BigInteger.
 195                  */
 196                 long quot = (i >>> 1) / 5;
 197                 long rem = i - quot * 10;
 198                 return toString(quot) + rem;
 199 
 200             case 16:
 201                 return toHexString(i);
 202 
 203             case 32:
 204                 return toUnsignedString0(i, 5);
 205 
 206             default:
 207                 return toUnsignedBigInteger(i).toString(radix);
 208             }
 209         }
 210     }
 211 
 212     /**
 213      * Return a BigInteger equal to the unsigned value of the
 214      * argument.
 215      */
 216     private static BigInteger toUnsignedBigInteger(long i) {
 217         if (i >= 0L)
 218             return BigInteger.valueOf(i);
 219         else {
 220             int upper = (int) (i >>> 32);
 221             int lower = (int) i;
 222 
 223             // return (upper << 32) + lower
 224             return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
 225                 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
 226         }
 227     }
 228 
 229     /**
 230      * Returns a string representation of the {@code long}
 231      * argument as an unsigned integer in base&nbsp;16.
 232      *
 233      * <p>The unsigned {@code long} value is the argument plus
 234      * 2<sup>64</sup> if the argument is negative; otherwise, it is
 235      * equal to the argument.  This value is converted to a string of
 236      * ASCII digits in hexadecimal (base&nbsp;16) with no extra
 237      * leading {@code 0}s.
 238      *
 239      * <p>The value of the argument can be recovered from the returned
 240      * string {@code s} by calling {@link
 241      * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
 242      * 16)}.
 243      *
 244      * <p>If the unsigned magnitude is zero, it is represented by a
 245      * single zero character {@code '0'} ({@code '\u005Cu0030'});
 246      * otherwise, the first character of the representation of the
 247      * unsigned magnitude will not be the zero character. The
 248      * following characters are used as hexadecimal digits:
 249      *
 250      * <blockquote>
 251      *  {@code 0123456789abcdef}
 252      * </blockquote>
 253      *
 254      * These are the characters {@code '\u005Cu0030'} through
 255      * {@code '\u005Cu0039'} and  {@code '\u005Cu0061'} through
 256      * {@code '\u005Cu0066'}.  If uppercase letters are desired,
 257      * the {@link java.lang.String#toUpperCase()} method may be called
 258      * on the result:
 259      *
 260      * <blockquote>
 261      *  {@code Long.toHexString(n).toUpperCase()}
 262      * </blockquote>
 263      *
 264      * @param   i   a {@code long} to be converted to a string.
 265      * @return  the string representation of the unsigned {@code long}
 266      *          value represented by the argument in hexadecimal
 267      *          (base&nbsp;16).
 268      * @see #parseUnsignedLong(String, int)
 269      * @see #toUnsignedString(long, int)
 270      * @since   1.0.2
 271      */
 272     public static String toHexString(long i) {
 273         return toUnsignedString0(i, 4);
 274     }
 275 
 276     /**
 277      * Returns a string representation of the {@code long}
 278      * argument as an unsigned integer in base&nbsp;8.
 279      *
 280      * <p>The unsigned {@code long} value is the argument plus
 281      * 2<sup>64</sup> if the argument is negative; otherwise, it is
 282      * equal to the argument.  This value is converted to a string of
 283      * ASCII digits in octal (base&nbsp;8) with no extra leading
 284      * {@code 0}s.
 285      *
 286      * <p>The value of the argument can be recovered from the returned
 287      * string {@code s} by calling {@link
 288      * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
 289      * 8)}.
 290      *
 291      * <p>If the unsigned magnitude is zero, it is represented by a
 292      * single zero character {@code '0'} ({@code '\u005Cu0030'});
 293      * otherwise, the first character of the representation of the
 294      * unsigned magnitude will not be the zero character. The
 295      * following characters are used as octal digits:
 296      *
 297      * <blockquote>
 298      *  {@code 01234567}
 299      * </blockquote>
 300      *
 301      * These are the characters {@code '\u005Cu0030'} through
 302      * {@code '\u005Cu0037'}.
 303      *
 304      * @param   i   a {@code long} to be converted to a string.
 305      * @return  the string representation of the unsigned {@code long}
 306      *          value represented by the argument in octal (base&nbsp;8).
 307      * @see #parseUnsignedLong(String, int)
 308      * @see #toUnsignedString(long, int)
 309      * @since   1.0.2
 310      */
 311     public static String toOctalString(long i) {
 312         return toUnsignedString0(i, 3);
 313     }
 314 
 315     /**
 316      * Returns a string representation of the {@code long}
 317      * argument as an unsigned integer in base&nbsp;2.
 318      *
 319      * <p>The unsigned {@code long} value is the argument plus
 320      * 2<sup>64</sup> if the argument is negative; otherwise, it is
 321      * equal to the argument.  This value is converted to a string of
 322      * ASCII digits in binary (base&nbsp;2) with no extra leading
 323      * {@code 0}s.
 324      *
 325      * <p>The value of the argument can be recovered from the returned
 326      * string {@code s} by calling {@link
 327      * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
 328      * 2)}.
 329      *
 330      * <p>If the unsigned magnitude is zero, it is represented by a
 331      * single zero character {@code '0'} ({@code '\u005Cu0030'});
 332      * otherwise, the first character of the representation of the
 333      * unsigned magnitude will not be the zero character. The
 334      * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
 335      * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
 336      *
 337      * @param   i   a {@code long} to be converted to a string.
 338      * @return  the string representation of the unsigned {@code long}
 339      *          value represented by the argument in binary (base&nbsp;2).
 340      * @see #parseUnsignedLong(String, int)
 341      * @see #toUnsignedString(long, int)
 342      * @since   1.0.2
 343      */
 344     public static String toBinaryString(long i) {
 345         return toUnsignedString0(i, 1);
 346     }
 347 
 348     /**
 349      * Format a long (treated as unsigned) into a String.
 350      * @param val the value to format
 351      * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
 352      */
 353     static String toUnsignedString0(long val, int shift) {
 354         // assert shift > 0 && shift <=5 : "Illegal shift value";
 355         int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
 356         int chars = Math.max(((mag + (shift - 1)) / shift), 1);
 357         char[] buf = new char[chars];
 358 
 359         formatUnsignedLong(val, shift, buf, 0, chars);
 360         return new String(buf, true);
 361     }
 362 
 363     /**
 364      * Format a long (treated as unsigned) into a character buffer. If
 365      * {@code len} exceeds the formatted ASCII representation of {@code val},
 366      * {@code buf} will be padded with leading zeroes.
 367      *
 368      * @param val the unsigned long to format
 369      * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
 370      * @param buf the character buffer to write to
 371      * @param offset the offset in the destination buffer to start at
 372      * @param len the number of characters to write
 373      */
 374      static void formatUnsignedLong(long val, int shift, char[] buf, int offset, int len) {
 375         // assert shift > 0 && shift <=5 : "Illegal shift value";
 376         // assert offset >= 0 && offset < buf.length : "illegal offset";
 377         // assert len > 0 && (offset + len) <= buf.length : "illegal length";
 378         int charPos = offset + len;
 379         int radix = 1 << shift;
 380         int mask = radix - 1;
 381         do {
 382             buf[--charPos] = Integer.digits[((int) val) & mask];
 383             val >>>= shift;
 384         } while (charPos > offset);
 385     }
 386 
 387     /**
 388      * Returns a {@code String} object representing the specified
 389      * {@code long}.  The argument is converted to signed decimal
 390      * representation and returned as a string, exactly as if the
 391      * argument and the radix 10 were given as arguments to the {@link
 392      * #toString(long, int)} method.
 393      *
 394      * @param   i   a {@code long} to be converted.
 395      * @return  a string representation of the argument in base&nbsp;10.
 396      */
 397     public static String toString(long i) {
 398         if (i == Long.MIN_VALUE)
 399             return "-9223372036854775808";
 400         int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
 401         char[] buf = new char[size];
 402         getChars(i, size, buf);
 403         return new String(buf, true);
 404     }
 405 
 406     /**
 407      * Returns a string representation of the argument as an unsigned
 408      * decimal value.
 409      *
 410      * The argument is converted to unsigned decimal representation
 411      * and returned as a string exactly as if the argument and radix
 412      * 10 were given as arguments to the {@link #toUnsignedString(long,
 413      * int)} method.
 414      *
 415      * @param   i  an integer to be converted to an unsigned string.
 416      * @return  an unsigned string representation of the argument.
 417      * @see     #toUnsignedString(long, int)
 418      * @since 1.8
 419      */
 420     public static String toUnsignedString(long i) {
 421         return toUnsignedString(i, 10);
 422     }
 423 
 424     /**
 425      * Places characters representing the integer i into the
 426      * character array buf. The characters are placed into
 427      * the buffer backwards starting with the least significant
 428      * digit at the specified index (exclusive), and working
 429      * backwards from there.
 430      *
 431      * Will fail if i == Long.MIN_VALUE
 432      */
 433     static void getChars(long i, int index, char[] buf) {
 434         long q;
 435         int r;
 436         int charPos = index;
 437         char sign = 0;
 438 
 439         if (i < 0) {
 440             sign = '-';
 441             i = -i;
 442         }
 443 
 444         // Get 2 digits/iteration using longs until quotient fits into an int
 445         while (i > Integer.MAX_VALUE) {
 446             q = i / 100;
 447             // really: r = i - (q * 100);
 448             r = (int)(i - ((q << 6) + (q << 5) + (q << 2)));
 449             i = q;
 450             buf[--charPos] = Integer.DigitOnes[r];
 451             buf[--charPos] = Integer.DigitTens[r];
 452         }
 453 
 454         // Get 2 digits/iteration using ints
 455         int q2;
 456         int i2 = (int)i;
 457         while (i2 >= 65536) {
 458             q2 = i2 / 100;
 459             // really: r = i2 - (q * 100);
 460             r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
 461             i2 = q2;
 462             buf[--charPos] = Integer.DigitOnes[r];
 463             buf[--charPos] = Integer.DigitTens[r];
 464         }
 465 
 466         // Fall thru to fast mode for smaller numbers
 467         // assert(i2 <= 65536, i2);
 468         for (;;) {
 469             q2 = (i2 * 52429) >>> (16+3);
 470             r = i2 - ((q2 << 3) + (q2 << 1));  // r = i2-(q2*10) ...
 471             buf[--charPos] = Integer.digits[r];
 472             i2 = q2;
 473             if (i2 == 0) break;
 474         }
 475         if (sign != 0) {
 476             buf[--charPos] = sign;
 477         }
 478     }
 479 
 480     // Requires positive x
 481     static int stringSize(long x) {
 482         long p = 10;
 483         for (int i=1; i<19; i++) {
 484             if (x < p)
 485                 return i;
 486             p = 10*p;
 487         }
 488         return 19;
 489     }
 490 
 491     /**
 492      * Parses the string argument as a signed {@code long} in the
 493      * radix specified by the second argument. The characters in the
 494      * string must all be digits of the specified radix (as determined
 495      * by whether {@link java.lang.Character#digit(char, int)} returns
 496      * a nonnegative value), except that the first character may be an
 497      * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
 498      * indicate a negative value or an ASCII plus sign {@code '+'}
 499      * ({@code '\u005Cu002B'}) to indicate a positive value. The
 500      * resulting {@code long} value is returned.
 501      *
 502      * <p>Note that neither the character {@code L}
 503      * ({@code '\u005Cu004C'}) nor {@code l}
 504      * ({@code '\u005Cu006C'}) is permitted to appear at the end
 505      * of the string as a type indicator, as would be permitted in
 506      * Java programming language source code - except that either
 507      * {@code L} or {@code l} may appear as a digit for a
 508      * radix greater than or equal to 22.
 509      *
 510      * <p>An exception of type {@code NumberFormatException} is
 511      * thrown if any of the following situations occurs:
 512      * <ul>
 513      *
 514      * <li>The first argument is {@code null} or is a string of
 515      * length zero.
 516      *
 517      * <li>The {@code radix} is either smaller than {@link
 518      * java.lang.Character#MIN_RADIX} or larger than {@link
 519      * java.lang.Character#MAX_RADIX}.
 520      *
 521      * <li>Any character of the string is not a digit of the specified
 522      * radix, except that the first character may be a minus sign
 523      * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
 524      * '+'} ({@code '\u005Cu002B'}) provided that the string is
 525      * longer than length 1.
 526      *
 527      * <li>The value represented by the string is not a value of type
 528      *      {@code long}.
 529      * </ul>
 530      *
 531      * <p>Examples:
 532      * <blockquote><pre>
 533      * parseLong("0", 10) returns 0L
 534      * parseLong("473", 10) returns 473L
 535      * parseLong("+42", 10) returns 42L
 536      * parseLong("-0", 10) returns 0L
 537      * parseLong("-FF", 16) returns -255L
 538      * parseLong("1100110", 2) returns 102L
 539      * parseLong("99", 8) throws a NumberFormatException
 540      * parseLong("Hazelnut", 10) throws a NumberFormatException
 541      * parseLong("Hazelnut", 36) returns 1356099454469L
 542      * </pre></blockquote>
 543      *
 544      * @param      s       the {@code String} containing the
 545      *                     {@code long} representation to be parsed.
 546      * @param      radix   the radix to be used while parsing {@code s}.
 547      * @return     the {@code long} represented by the string argument in
 548      *             the specified radix.
 549      * @throws     NumberFormatException  if the string does not contain a
 550      *             parsable {@code long}.
 551      */
 552     public static long parseLong(String s, int radix)
 553               throws NumberFormatException
 554     {
 555         if (s == null) {
 556             throw new NumberFormatException("null");
 557         }
 558 
 559         if (radix < Character.MIN_RADIX) {
 560             throw new NumberFormatException("radix " + radix +
 561                                             " less than Character.MIN_RADIX");
 562         }
 563         if (radix > Character.MAX_RADIX) {
 564             throw new NumberFormatException("radix " + radix +
 565                                             " greater than Character.MAX_RADIX");
 566         }
 567 
 568         boolean negative = false;
 569         int i = 0, len = s.length();
 570         long limit = -Long.MAX_VALUE;
 571 
 572         if (len > 0) {
 573             char firstChar = s.charAt(0);
 574             if (firstChar < '0') { // Possible leading "+" or "-"
 575                 if (firstChar == '-') {
 576                     negative = true;
 577                     limit = Long.MIN_VALUE;
 578                 } else if (firstChar != '+') {
 579                     throw NumberFormatException.forInputString(s);
 580                 }
 581 
 582                 if (len == 1) { // Cannot have lone "+" or "-"
 583                     throw NumberFormatException.forInputString(s);
 584                 }
 585                 i++;
 586             }
 587             long multmin = limit / radix;
 588             long result = 0;
 589             while (i < len) {
 590                 // Accumulating negatively avoids surprises near MAX_VALUE
 591                 int digit = Character.digit(s.charAt(i++),radix);
 592                 if (digit < 0 || result < multmin) {
 593                     throw NumberFormatException.forInputString(s);
 594                 }
 595                 result *= radix;
 596                 if (result < limit + digit) {
 597                     throw NumberFormatException.forInputString(s);
 598                 }
 599                 result -= digit;
 600             }
 601             return negative ? result : -result;
 602         } else {
 603             throw NumberFormatException.forInputString(s);
 604         }
 605     }
 606 
 607     /**
 608      * Parses the {@link CharSequence} argument as a signed {@code long} in
 609      * the specified {@code radix}, beginning at the specified
 610      * {@code beginIndex} and extending to {@code endIndex - 1}.
 611      *
 612      * <p>The method does not take steps to guard against the
 613      * {@code CharSequence} being mutated while parsing.
 614      *
 615      * @param      s   the {@code CharSequence} containing the {@code long}
 616      *                  representation to be parsed
 617      * @param      beginIndex   the beginning index, inclusive.
 618      * @param      endIndex     the ending index, exclusive.
 619      * @param      radix   the radix to be used while parsing {@code s}.
 620      * @return     the signed {@code long} represented by the subsequence in
 621      *             the specified radix.
 622      * @throws     NullPointerException  if {@code s} is null.
 623      * @throws     IndexOutOfBoundsException  if {@code beginIndex} is
 624      *             negative, or if {@code beginIndex} is greater than
 625      *             {@code endIndex} or if {@code endIndex} is greater than
 626      *             {@code s.length()}.
 627      * @throws     NumberFormatException  if the {@code CharSequence} does not
 628      *             contain a parsable {@code int} in the specified
 629      *             {@code radix}, or if {@code radix} is either smaller than
 630      *             {@link java.lang.Character#MIN_RADIX} or larger than
 631      *             {@link java.lang.Character#MAX_RADIX}.
 632      * @since  1.9
 633      */
 634     public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
 635                 throws NumberFormatException {
 636         s = Objects.requireNonNull(s);
 637 
 638         if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
 639             throw new IndexOutOfBoundsException();
 640         }
 641         if (radix < Character.MIN_RADIX) {
 642             throw new NumberFormatException("radix " + radix +
 643                     " less than Character.MIN_RADIX");
 644         }
 645         if (radix > Character.MAX_RADIX) {
 646             throw new NumberFormatException("radix " + radix +
 647                     " greater than Character.MAX_RADIX");
 648         }
 649 
 650         boolean negative = false;
 651         int i = beginIndex;
 652         long limit = -Long.MAX_VALUE;
 653 
 654         if (i < endIndex) {
 655             char firstChar = s.charAt(i);
 656             if (firstChar < '0') { // Possible leading "+" or "-"
 657                 if (firstChar == '-') {
 658                     negative = true;
 659                     limit = Long.MIN_VALUE;
 660                 } else if (firstChar != '+') {
 661                     throw NumberFormatException.forCharSequence(s, beginIndex,
 662                             endIndex, i);
 663                 }
 664                 i++;
 665             }
 666             if (i >= endIndex) { // Cannot have lone "+", "-" or ""
 667                 throw NumberFormatException.forCharSequence(s, beginIndex,
 668                         endIndex, i);
 669             }
 670             long multmin = limit / radix;
 671             long result = 0;
 672             while (i < endIndex) {
 673                 // Accumulating negatively avoids surprises near MAX_VALUE
 674                 int digit = Character.digit(s.charAt(i), radix);
 675                 if (digit < 0 || result < multmin) {
 676                     throw NumberFormatException.forCharSequence(s, beginIndex,
 677                             endIndex, i);
 678                 }
 679                 result *= radix;
 680                 if (result < limit + digit) {
 681                     throw NumberFormatException.forCharSequence(s, beginIndex,
 682                             endIndex, i);
 683                 }
 684                 i++;
 685                 result -= digit;
 686             }
 687             return negative ? result : -result;
 688         } else {
 689             throw new NumberFormatException("");
 690         }
 691     }
 692 
 693     /**
 694      * Parses the string argument as a signed decimal {@code long}.
 695      * The characters in the string must all be decimal digits, except
 696      * that the first character may be an ASCII minus sign {@code '-'}
 697      * ({@code \u005Cu002D'}) to indicate a negative value or an
 698      * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
 699      * indicate a positive value. The resulting {@code long} value is
 700      * returned, exactly as if the argument and the radix {@code 10}
 701      * were given as arguments to the {@link
 702      * #parseLong(java.lang.String, int)} method.
 703      *
 704      * <p>Note that neither the character {@code L}
 705      * ({@code '\u005Cu004C'}) nor {@code l}
 706      * ({@code '\u005Cu006C'}) is permitted to appear at the end
 707      * of the string as a type indicator, as would be permitted in
 708      * Java programming language source code.
 709      *
 710      * @param      s   a {@code String} containing the {@code long}
 711      *             representation to be parsed
 712      * @return     the {@code long} represented by the argument in
 713      *             decimal.
 714      * @throws     NumberFormatException  if the string does not contain a
 715      *             parsable {@code long}.
 716      */
 717     public static long parseLong(String s) throws NumberFormatException {
 718         return parseLong(s, 10);
 719     }
 720 
 721     /**
 722      * Parses the string argument as an unsigned {@code long} in the
 723      * radix specified by the second argument.  An unsigned integer
 724      * maps the values usually associated with negative numbers to
 725      * positive numbers larger than {@code MAX_VALUE}.
 726      *
 727      * The characters in the string must all be digits of the
 728      * specified radix (as determined by whether {@link
 729      * java.lang.Character#digit(char, int)} returns a nonnegative
 730      * value), except that the first character may be an ASCII plus
 731      * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
 732      * integer value is returned.
 733      *
 734      * <p>An exception of type {@code NumberFormatException} is
 735      * thrown if any of the following situations occurs:
 736      * <ul>
 737      * <li>The first argument is {@code null} or is a string of
 738      * length zero.
 739      *
 740      * <li>The radix is either smaller than
 741      * {@link java.lang.Character#MIN_RADIX} or
 742      * larger than {@link java.lang.Character#MAX_RADIX}.
 743      *
 744      * <li>Any character of the string is not a digit of the specified
 745      * radix, except that the first character may be a plus sign
 746      * {@code '+'} ({@code '\u005Cu002B'}) provided that the
 747      * string is longer than length 1.
 748      *
 749      * <li>The value represented by the string is larger than the
 750      * largest unsigned {@code long}, 2<sup>64</sup>-1.
 751      *
 752      * </ul>
 753      *
 754      *
 755      * @param      s   the {@code String} containing the unsigned integer
 756      *                  representation to be parsed
 757      * @param      radix   the radix to be used while parsing {@code s}.
 758      * @return     the unsigned {@code long} represented by the string
 759      *             argument in the specified radix.
 760      * @throws     NumberFormatException if the {@code String}
 761      *             does not contain a parsable {@code long}.
 762      * @since 1.8
 763      */
 764     public static long parseUnsignedLong(String s, int radix)
 765                 throws NumberFormatException {
 766         if (s == null)  {
 767             throw new NumberFormatException("null");
 768         }
 769 
 770         int len = s.length();
 771         if (len > 0) {
 772             char firstChar = s.charAt(0);
 773             if (firstChar == '-') {
 774                 throw new
 775                     NumberFormatException(String.format("Illegal leading minus sign " +
 776                                                        "on unsigned string %s.", s));
 777             } else {
 778                 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
 779                     (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
 780                     return parseLong(s, radix);
 781                 }
 782 
 783                 // No need for range checks on len due to testing above.
 784                 long first = parseLong(s, 0, len - 1, radix);
 785                 int second = Character.digit(s.charAt(len - 1), radix);
 786                 if (second < 0) {
 787                     throw new NumberFormatException("Bad digit at end of " + s);
 788                 }
 789                 long result = first * radix + second;
 790 
 791                 /*
 792                  * Test leftmost bits of multiprecision extension of first*radix
 793                  * for overflow. The number of bits needed is defined by
 794                  * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
 795                  * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
 796                  * overflow is tested by splitting guard in the ranges
 797                  * guard < 92, 92 <= guard < 128, and 128 <= guard, where
 798                  * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
 799                  * on a value which does not include a prime factor in the legal
 800                  * radix range.
 801                  */
 802                 int guard = radix * (int) (first >>> 57);
 803                 if (guard >= 128 ||
 804                     (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
 805                     /*
 806                      * For purposes of exposition, the programmatic statements
 807                      * below should be taken to be multi-precision, i.e., not
 808                      * subject to overflow.
 809                      *
 810                      * A) Condition guard >= 128:
 811                      * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
 812                      * hence always overflow.
 813                      *
 814                      * B) Condition guard < 92:
 815                      * Define left7 = first >>> 57.
 816                      * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
 817                      * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
 818                      * Thus if radix*left7 < 92, radix <= 36, and second < 36,
 819                      * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
 820                      * never overflow.
 821                      *
 822                      * C) Condition 92 <= guard < 128:
 823                      * first*radix + second >= radix*left7*2^57 + second
 824                      * so that first*radix + second >= 92*2^57 + 0 > 2^63
 825                      *
 826                      * D) Condition guard < 128:
 827                      * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
 828                      * so
 829                      * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
 830                      * thus
 831                      * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
 832                      * whence
 833                      * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
 834                      *
 835                      * E) Conditions C, D, and result >= 0:
 836                      * C and D combined imply the mathematical result
 837                      * 2^63 < first*radix + second < 2^64 + 2^63. The lower
 838                      * bound is therefore negative as a signed long, but the
 839                      * upper bound is too small to overflow again after the
 840                      * signed long overflows to positive above 2^64 - 1. Hence
 841                      * result >= 0 implies overflow given C and D.
 842                      */
 843                     throw new NumberFormatException(String.format("String value %s exceeds " +
 844                                                                   "range of unsigned long.", s));
 845                 }
 846                 return result;
 847             }
 848         } else {
 849             throw NumberFormatException.forInputString(s);
 850         }
 851     }
 852 
 853     /**
 854      * Parses the {@link CharSequence} argument as an unsigned {@code long} in
 855      * the specified {@code radix}, beginning at the specified
 856      * {@code beginIndex} and extending to {@code endIndex - 1}.
 857      *
 858      * <p>The method does not take steps to guard against the
 859      * {@code CharSequence} being mutated while parsing.
 860      *
 861      * @param      s   the {@code CharSequence} containing the unsigned
 862      *                 {@code long} representation to be parsed
 863      * @param      beginIndex   the beginning index, inclusive.
 864      * @param      endIndex     the ending index, exclusive.
 865      * @param      radix   the radix to be used while parsing {@code s}.
 866      * @return     the unsigned {@code long} represented by the subsequence in
 867      *             the specified radix.
 868      * @throws     NullPointerException  if {@code s} is null.
 869      * @throws     IndexOutOfBoundsException  if {@code beginIndex} is
 870      *             negative, or if {@code beginIndex} is greater than
 871      *             {@code endIndex} or if {@code endIndex} is greater than
 872      *             {@code s.length()}.
 873      * @throws     NumberFormatException  if the {@code CharSequence} does not
 874      *             contain a parsable unsigned {@code long} in the specified
 875      *             {@code radix}, or if {@code radix} is either smaller than
 876      *             {@link java.lang.Character#MIN_RADIX} or larger than
 877      *             {@link java.lang.Character#MAX_RADIX}.
 878      * @since  1.9
 879      */
 880     public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
 881                 throws NumberFormatException {
 882         s = Objects.requireNonNull(s);
 883 
 884         if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
 885             throw new IndexOutOfBoundsException();
 886         }
 887         int start = beginIndex, len = endIndex - beginIndex;
 888 
 889         if (len > 0) {
 890             char firstChar = s.charAt(start);
 891             if (firstChar == '-') {
 892                 throw new NumberFormatException(String.format("Illegal leading minus sign " +
 893                         "on unsigned string %s.", s.subSequence(start, start + len)));
 894             } else {
 895                 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
 896                     (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
 897                     return parseLong(s, start, start + len, radix);
 898                 }
 899 
 900                 // No need for range checks on end due to testing above.
 901                 long first = parseLong(s, start, start + len - 1, radix);
 902                 int second = Character.digit(s.charAt(start + len - 1), radix);
 903                 if (second < 0) {
 904                     throw new NumberFormatException("Bad digit at end of " +
 905                             s.subSequence(start, start + len));
 906                 }
 907                 long result = first * radix + second;
 908 
 909                 /*
 910                  * Test leftmost bits of multiprecision extension of first*radix
 911                  * for overflow. The number of bits needed is defined by
 912                  * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
 913                  * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
 914                  * overflow is tested by splitting guard in the ranges
 915                  * guard < 92, 92 <= guard < 128, and 128 <= guard, where
 916                  * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
 917                  * on a value which does not include a prime factor in the legal
 918                  * radix range.
 919                  */
 920                 int guard = radix * (int) (first >>> 57);
 921                 if (guard >= 128 ||
 922                         (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
 923                     /*
 924                      * For purposes of exposition, the programmatic statements
 925                      * below should be taken to be multi-precision, i.e., not
 926                      * subject to overflow.
 927                      *
 928                      * A) Condition guard >= 128:
 929                      * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
 930                      * hence always overflow.
 931                      *
 932                      * B) Condition guard < 92:
 933                      * Define left7 = first >>> 57.
 934                      * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
 935                      * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
 936                      * Thus if radix*left7 < 92, radix <= 36, and second < 36,
 937                      * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
 938                      * never overflow.
 939                      *
 940                      * C) Condition 92 <= guard < 128:
 941                      * first*radix + second >= radix*left7*2^57 + second
 942                      * so that first*radix + second >= 92*2^57 + 0 > 2^63
 943                      *
 944                      * D) Condition guard < 128:
 945                      * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
 946                      * so
 947                      * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
 948                      * thus
 949                      * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
 950                      * whence
 951                      * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
 952                      *
 953                      * E) Conditions C, D, and result >= 0:
 954                      * C and D combined imply the mathematical result
 955                      * 2^63 < first*radix + second < 2^64 + 2^63. The lower
 956                      * bound is therefore negative as a signed long, but the
 957                      * upper bound is too small to overflow again after the
 958                      * signed long overflows to positive above 2^64 - 1. Hence
 959                      * result >= 0 implies overflow given C and D.
 960                      */
 961                     throw new NumberFormatException(String.format("String value %s exceeds " +
 962                             "range of unsigned long.", s.subSequence(start, start + len)));
 963                 }
 964                 return result;
 965             }
 966         } else {
 967             throw NumberFormatException.forInputString("");
 968         }
 969     }
 970 
 971     /**
 972      * Parses the string argument as an unsigned decimal {@code long}. The
 973      * characters in the string must all be decimal digits, except
 974      * that the first character may be an ASCII plus sign {@code
 975      * '+'} ({@code '\u005Cu002B'}). The resulting integer value
 976      * is returned, exactly as if the argument and the radix 10 were
 977      * given as arguments to the {@link
 978      * #parseUnsignedLong(java.lang.String, int)} method.
 979      *
 980      * @param s   a {@code String} containing the unsigned {@code long}
 981      *            representation to be parsed
 982      * @return    the unsigned {@code long} value represented by the decimal string argument
 983      * @throws    NumberFormatException  if the string does not contain a
 984      *            parsable unsigned integer.
 985      * @since 1.8
 986      */
 987     public static long parseUnsignedLong(String s) throws NumberFormatException {
 988         return parseUnsignedLong(s, 10);
 989     }
 990 
 991     /**
 992      * Returns a {@code Long} object holding the value
 993      * extracted from the specified {@code String} when parsed
 994      * with the radix given by the second argument.  The first
 995      * argument is interpreted as representing a signed
 996      * {@code long} in the radix specified by the second
 997      * argument, exactly as if the arguments were given to the {@link
 998      * #parseLong(java.lang.String, int)} method. The result is a
 999      * {@code Long} object that represents the {@code long}
1000      * value specified by the string.
1001      *
1002      * <p>In other words, this method returns a {@code Long} object equal
1003      * to the value of:
1004      *
1005      * <blockquote>
1006      *  {@code new Long(Long.parseLong(s, radix))}
1007      * </blockquote>
1008      *
1009      * @param      s       the string to be parsed
1010      * @param      radix   the radix to be used in interpreting {@code s}
1011      * @return     a {@code Long} object holding the value
1012      *             represented by the string argument in the specified
1013      *             radix.
1014      * @throws     NumberFormatException  If the {@code String} does not
1015      *             contain a parsable {@code long}.
1016      */
1017     public static Long valueOf(String s, int radix) throws NumberFormatException {
1018         return Long.valueOf(parseLong(s, radix));
1019     }
1020 
1021     /**
1022      * Returns a {@code Long} object holding the value
1023      * of the specified {@code String}. The argument is
1024      * interpreted as representing a signed decimal {@code long},
1025      * exactly as if the argument were given to the {@link
1026      * #parseLong(java.lang.String)} method. The result is a
1027      * {@code Long} object that represents the integer value
1028      * specified by the string.
1029      *
1030      * <p>In other words, this method returns a {@code Long} object
1031      * equal to the value of:
1032      *
1033      * <blockquote>
1034      *  {@code new Long(Long.parseLong(s))}
1035      * </blockquote>
1036      *
1037      * @param      s   the string to be parsed.
1038      * @return     a {@code Long} object holding the value
1039      *             represented by the string argument.
1040      * @throws     NumberFormatException  If the string cannot be parsed
1041      *             as a {@code long}.
1042      */
1043     public static Long valueOf(String s) throws NumberFormatException
1044     {
1045         return Long.valueOf(parseLong(s, 10));
1046     }
1047 
1048     private static class LongCache {
1049         private LongCache(){}
1050 
1051         static final Long cache[] = new Long[-(-128) + 127 + 1];
1052 
1053         static {
1054             for(int i = 0; i < cache.length; i++)
1055                 cache[i] = new Long(i - 128);
1056         }
1057     }
1058 
1059     /**
1060      * Returns a {@code Long} instance representing the specified
1061      * {@code long} value.
1062      * If a new {@code Long} instance is not required, this method
1063      * should generally be used in preference to the constructor
1064      * {@link #Long(long)}, as this method is likely to yield
1065      * significantly better space and time performance by caching
1066      * frequently requested values.
1067      *
1068      * Note that unlike the {@linkplain Integer#valueOf(int)
1069      * corresponding method} in the {@code Integer} class, this method
1070      * is <em>not</em> required to cache values within a particular
1071      * range.
1072      *
1073      * @param  l a long value.
1074      * @return a {@code Long} instance representing {@code l}.
1075      * @since  1.5
1076      */
1077     public static Long valueOf(long l) {
1078         final int offset = 128;
1079         if (l >= -128 && l <= 127) { // will cache
1080             return LongCache.cache[(int)l + offset];
1081         }
1082         return new Long(l);
1083     }
1084 
1085     /**
1086      * Decodes a {@code String} into a {@code Long}.
1087      * Accepts decimal, hexadecimal, and octal numbers given by the
1088      * following grammar:
1089      *
1090      * <blockquote>
1091      * <dl>
1092      * <dt><i>DecodableString:</i>
1093      * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1094      * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1095      * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1096      * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1097      * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1098      *
1099      * <dt><i>Sign:</i>
1100      * <dd>{@code -}
1101      * <dd>{@code +}
1102      * </dl>
1103      * </blockquote>
1104      *
1105      * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1106      * are as defined in section 3.10.1 of
1107      * <cite>The Java&trade; Language Specification</cite>,
1108      * except that underscores are not accepted between digits.
1109      *
1110      * <p>The sequence of characters following an optional
1111      * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1112      * "{@code #}", or leading zero) is parsed as by the {@code
1113      * Long.parseLong} method with the indicated radix (10, 16, or 8).
1114      * This sequence of characters must represent a positive value or
1115      * a {@link NumberFormatException} will be thrown.  The result is
1116      * negated if first character of the specified {@code String} is
1117      * the minus sign.  No whitespace characters are permitted in the
1118      * {@code String}.
1119      *
1120      * @param     nm the {@code String} to decode.
1121      * @return    a {@code Long} object holding the {@code long}
1122      *            value represented by {@code nm}
1123      * @throws    NumberFormatException  if the {@code String} does not
1124      *            contain a parsable {@code long}.
1125      * @see java.lang.Long#parseLong(String, int)
1126      * @since 1.2
1127      */
1128     public static Long decode(String nm) throws NumberFormatException {
1129         int radix = 10;
1130         int index = 0;
1131         boolean negative = false;
1132         Long result;
1133 
1134         if (nm.length() == 0)
1135             throw new NumberFormatException("Zero length string");
1136         char firstChar = nm.charAt(0);
1137         // Handle sign, if present
1138         if (firstChar == '-') {
1139             negative = true;
1140             index++;
1141         } else if (firstChar == '+')
1142             index++;
1143 
1144         // Handle radix specifier, if present
1145         if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1146             index += 2;
1147             radix = 16;
1148         }
1149         else if (nm.startsWith("#", index)) {
1150             index ++;
1151             radix = 16;
1152         }
1153         else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1154             index ++;
1155             radix = 8;
1156         }
1157 
1158         if (nm.startsWith("-", index) || nm.startsWith("+", index))
1159             throw new NumberFormatException("Sign character in wrong position");
1160 
1161         try {
1162             result = Long.valueOf(nm.substring(index), radix);
1163             result = negative ? Long.valueOf(-result.longValue()) : result;
1164         } catch (NumberFormatException e) {
1165             // If number is Long.MIN_VALUE, we'll end up here. The next line
1166             // handles this case, and causes any genuine format error to be
1167             // rethrown.
1168             String constant = negative ? ("-" + nm.substring(index))
1169                                        : nm.substring(index);
1170             result = Long.valueOf(constant, radix);
1171         }
1172         return result;
1173     }
1174 
1175     /**
1176      * The value of the {@code Long}.
1177      *
1178      * @serial
1179      */
1180     private final long value;
1181 
1182     /**
1183      * Constructs a newly allocated {@code Long} object that
1184      * represents the specified {@code long} argument.
1185      *
1186      * @param   value   the value to be represented by the
1187      *          {@code Long} object.
1188      */
1189     public Long(long value) {
1190         this.value = value;
1191     }
1192 
1193     /**
1194      * Constructs a newly allocated {@code Long} object that
1195      * represents the {@code long} value indicated by the
1196      * {@code String} parameter. The string is converted to a
1197      * {@code long} value in exactly the manner used by the
1198      * {@code parseLong} method for radix 10.
1199      *
1200      * @param      s   the {@code String} to be converted to a
1201      *             {@code Long}.
1202      * @throws     NumberFormatException  if the {@code String} does not
1203      *             contain a parsable {@code long}.
1204      * @see        java.lang.Long#parseLong(java.lang.String, int)
1205      */
1206     public Long(String s) throws NumberFormatException {
1207         this.value = parseLong(s, 10);
1208     }
1209 
1210     /**
1211      * Returns the value of this {@code Long} as a {@code byte} after
1212      * a narrowing primitive conversion.
1213      * @jls 5.1.3 Narrowing Primitive Conversions
1214      */
1215     public byte byteValue() {
1216         return (byte)value;
1217     }
1218 
1219     /**
1220      * Returns the value of this {@code Long} as a {@code short} after
1221      * a narrowing primitive conversion.
1222      * @jls 5.1.3 Narrowing Primitive Conversions
1223      */
1224     public short shortValue() {
1225         return (short)value;
1226     }
1227 
1228     /**
1229      * Returns the value of this {@code Long} as an {@code int} after
1230      * a narrowing primitive conversion.
1231      * @jls 5.1.3 Narrowing Primitive Conversions
1232      */
1233     public int intValue() {
1234         return (int)value;
1235     }
1236 
1237     /**
1238      * Returns the value of this {@code Long} as a
1239      * {@code long} value.
1240      */
1241     public long longValue() {
1242         return value;
1243     }
1244 
1245     /**
1246      * Returns the value of this {@code Long} as a {@code float} after
1247      * a widening primitive conversion.
1248      * @jls 5.1.2 Widening Primitive Conversions
1249      */
1250     public float floatValue() {
1251         return (float)value;
1252     }
1253 
1254     /**
1255      * Returns the value of this {@code Long} as a {@code double}
1256      * after a widening primitive conversion.
1257      * @jls 5.1.2 Widening Primitive Conversions
1258      */
1259     public double doubleValue() {
1260         return (double)value;
1261     }
1262 
1263     /**
1264      * Returns a {@code String} object representing this
1265      * {@code Long}'s value.  The value is converted to signed
1266      * decimal representation and returned as a string, exactly as if
1267      * the {@code long} value were given as an argument to the
1268      * {@link java.lang.Long#toString(long)} method.
1269      *
1270      * @return  a string representation of the value of this object in
1271      *          base&nbsp;10.
1272      */
1273     public String toString() {
1274         return toString(value);
1275     }
1276 
1277     /**
1278      * Returns a hash code for this {@code Long}. The result is
1279      * the exclusive OR of the two halves of the primitive
1280      * {@code long} value held by this {@code Long}
1281      * object. That is, the hashcode is the value of the expression:
1282      *
1283      * <blockquote>
1284      *  {@code (int)(this.longValue()^(this.longValue()>>>32))}
1285      * </blockquote>
1286      *
1287      * @return  a hash code value for this object.
1288      */
1289     @Override
1290     public int hashCode() {
1291         return Long.hashCode(value);
1292     }
1293 
1294     /**
1295      * Returns a hash code for a {@code long} value; compatible with
1296      * {@code Long.hashCode()}.
1297      *
1298      * @param value the value to hash
1299      * @return a hash code value for a {@code long} value.
1300      * @since 1.8
1301      */
1302     public static int hashCode(long value) {
1303         return (int)(value ^ (value >>> 32));
1304     }
1305 
1306     /**
1307      * Compares this object to the specified object.  The result is
1308      * {@code true} if and only if the argument is not
1309      * {@code null} and is a {@code Long} object that
1310      * contains the same {@code long} value as this object.
1311      *
1312      * @param   obj   the object to compare with.
1313      * @return  {@code true} if the objects are the same;
1314      *          {@code false} otherwise.
1315      */
1316     public boolean equals(Object obj) {
1317         if (obj instanceof Long) {
1318             return value == ((Long)obj).longValue();
1319         }
1320         return false;
1321     }
1322 
1323     /**
1324      * Determines the {@code long} value of the system property
1325      * with the specified name.
1326      *
1327      * <p>The first argument is treated as the name of a system
1328      * property.  System properties are accessible through the {@link
1329      * java.lang.System#getProperty(java.lang.String)} method. The
1330      * string value of this property is then interpreted as a {@code
1331      * long} value using the grammar supported by {@link Long#decode decode}
1332      * and a {@code Long} object representing this value is returned.
1333      *
1334      * <p>If there is no property with the specified name, if the
1335      * specified name is empty or {@code null}, or if the property
1336      * does not have the correct numeric format, then {@code null} is
1337      * returned.
1338      *
1339      * <p>In other words, this method returns a {@code Long} object
1340      * equal to the value of:
1341      *
1342      * <blockquote>
1343      *  {@code getLong(nm, null)}
1344      * </blockquote>
1345      *
1346      * @param   nm   property name.
1347      * @return  the {@code Long} value of the property.
1348      * @throws  SecurityException for the same reasons as
1349      *          {@link System#getProperty(String) System.getProperty}
1350      * @see     java.lang.System#getProperty(java.lang.String)
1351      * @see     java.lang.System#getProperty(java.lang.String, java.lang.String)
1352      */
1353     public static Long getLong(String nm) {
1354         return getLong(nm, null);
1355     }
1356 
1357     /**
1358      * Determines the {@code long} value of the system property
1359      * with the specified name.
1360      *
1361      * <p>The first argument is treated as the name of a system
1362      * property.  System properties are accessible through the {@link
1363      * java.lang.System#getProperty(java.lang.String)} method. The
1364      * string value of this property is then interpreted as a {@code
1365      * long} value using the grammar supported by {@link Long#decode decode}
1366      * and a {@code Long} object representing this value is returned.
1367      *
1368      * <p>The second argument is the default value. A {@code Long} object
1369      * that represents the value of the second argument is returned if there
1370      * is no property of the specified name, if the property does not have
1371      * the correct numeric format, or if the specified name is empty or null.
1372      *
1373      * <p>In other words, this method returns a {@code Long} object equal
1374      * to the value of:
1375      *
1376      * <blockquote>
1377      *  {@code getLong(nm, new Long(val))}
1378      * </blockquote>
1379      *
1380      * but in practice it may be implemented in a manner such as:
1381      *
1382      * <blockquote><pre>
1383      * Long result = getLong(nm, null);
1384      * return (result == null) ? new Long(val) : result;
1385      * </pre></blockquote>
1386      *
1387      * to avoid the unnecessary allocation of a {@code Long} object when
1388      * the default value is not needed.
1389      *
1390      * @param   nm    property name.
1391      * @param   val   default value.
1392      * @return  the {@code Long} value of the property.
1393      * @throws  SecurityException for the same reasons as
1394      *          {@link System#getProperty(String) System.getProperty}
1395      * @see     java.lang.System#getProperty(java.lang.String)
1396      * @see     java.lang.System#getProperty(java.lang.String, java.lang.String)
1397      */
1398     public static Long getLong(String nm, long val) {
1399         Long result = Long.getLong(nm, null);
1400         return (result == null) ? Long.valueOf(val) : result;
1401     }
1402 
1403     /**
1404      * Returns the {@code long} value of the system property with
1405      * the specified name.  The first argument is treated as the name
1406      * of a system property.  System properties are accessible through
1407      * the {@link java.lang.System#getProperty(java.lang.String)}
1408      * method. The string value of this property is then interpreted
1409      * as a {@code long} value, as per the
1410      * {@link Long#decode decode} method, and a {@code Long} object
1411      * representing this value is returned; in summary:
1412      *
1413      * <ul>
1414      * <li>If the property value begins with the two ASCII characters
1415      * {@code 0x} or the ASCII character {@code #}, not followed by
1416      * a minus sign, then the rest of it is parsed as a hexadecimal integer
1417      * exactly as for the method {@link #valueOf(java.lang.String, int)}
1418      * with radix 16.
1419      * <li>If the property value begins with the ASCII character
1420      * {@code 0} followed by another character, it is parsed as
1421      * an octal integer exactly as by the method {@link
1422      * #valueOf(java.lang.String, int)} with radix 8.
1423      * <li>Otherwise the property value is parsed as a decimal
1424      * integer exactly as by the method
1425      * {@link #valueOf(java.lang.String, int)} with radix 10.
1426      * </ul>
1427      *
1428      * <p>Note that, in every case, neither {@code L}
1429      * ({@code '\u005Cu004C'}) nor {@code l}
1430      * ({@code '\u005Cu006C'}) is permitted to appear at the end
1431      * of the property value as a type indicator, as would be
1432      * permitted in Java programming language source code.
1433      *
1434      * <p>The second argument is the default value. The default value is
1435      * returned if there is no property of the specified name, if the
1436      * property does not have the correct numeric format, or if the
1437      * specified name is empty or {@code null}.
1438      *
1439      * @param   nm   property name.
1440      * @param   val   default value.
1441      * @return  the {@code Long} value of the property.
1442      * @throws  SecurityException for the same reasons as
1443      *          {@link System#getProperty(String) System.getProperty}
1444      * @see     System#getProperty(java.lang.String)
1445      * @see     System#getProperty(java.lang.String, java.lang.String)
1446      */
1447     public static Long getLong(String nm, Long val) {
1448         String v = null;
1449         try {
1450             v = System.getProperty(nm);
1451         } catch (IllegalArgumentException | NullPointerException e) {
1452         }
1453         if (v != null) {
1454             try {
1455                 return Long.decode(v);
1456             } catch (NumberFormatException e) {
1457             }
1458         }
1459         return val;
1460     }
1461 
1462     /**
1463      * Compares two {@code Long} objects numerically.
1464      *
1465      * @param   anotherLong   the {@code Long} to be compared.
1466      * @return  the value {@code 0} if this {@code Long} is
1467      *          equal to the argument {@code Long}; a value less than
1468      *          {@code 0} if this {@code Long} is numerically less
1469      *          than the argument {@code Long}; and a value greater
1470      *          than {@code 0} if this {@code Long} is numerically
1471      *           greater than the argument {@code Long} (signed
1472      *           comparison).
1473      * @since   1.2
1474      */
1475     public int compareTo(Long anotherLong) {
1476         return compare(this.value, anotherLong.value);
1477     }
1478 
1479     /**
1480      * Compares two {@code long} values numerically.
1481      * The value returned is identical to what would be returned by:
1482      * <pre>
1483      *    Long.valueOf(x).compareTo(Long.valueOf(y))
1484      * </pre>
1485      *
1486      * @param  x the first {@code long} to compare
1487      * @param  y the second {@code long} to compare
1488      * @return the value {@code 0} if {@code x == y};
1489      *         a value less than {@code 0} if {@code x < y}; and
1490      *         a value greater than {@code 0} if {@code x > y}
1491      * @since 1.7
1492      */
1493     public static int compare(long x, long y) {
1494         return (x < y) ? -1 : ((x == y) ? 0 : 1);
1495     }
1496 
1497     /**
1498      * Compares two {@code long} values numerically treating the values
1499      * as unsigned.
1500      *
1501      * @param  x the first {@code long} to compare
1502      * @param  y the second {@code long} to compare
1503      * @return the value {@code 0} if {@code x == y}; a value less
1504      *         than {@code 0} if {@code x < y} as unsigned values; and
1505      *         a value greater than {@code 0} if {@code x > y} as
1506      *         unsigned values
1507      * @since 1.8
1508      */
1509     public static int compareUnsigned(long x, long y) {
1510         return compare(x + MIN_VALUE, y + MIN_VALUE);
1511     }
1512 
1513 
1514     /**
1515      * Returns the unsigned quotient of dividing the first argument by
1516      * the second where each argument and the result is interpreted as
1517      * an unsigned value.
1518      *
1519      * <p>Note that in two's complement arithmetic, the three other
1520      * basic arithmetic operations of add, subtract, and multiply are
1521      * bit-wise identical if the two operands are regarded as both
1522      * being signed or both being unsigned.  Therefore separate {@code
1523      * addUnsigned}, etc. methods are not provided.
1524      *
1525      * @param dividend the value to be divided
1526      * @param divisor the value doing the dividing
1527      * @return the unsigned quotient of the first argument divided by
1528      * the second argument
1529      * @see #remainderUnsigned
1530      * @since 1.8
1531      */
1532     public static long divideUnsigned(long dividend, long divisor) {
1533         if (divisor < 0L) { // signed comparison
1534             // Answer must be 0 or 1 depending on relative magnitude
1535             // of dividend and divisor.
1536             return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L;
1537         }
1538 
1539         if (dividend > 0) //  Both inputs non-negative
1540             return dividend/divisor;
1541         else {
1542             /*
1543              * For simple code, leveraging BigInteger.  Longer and faster
1544              * code written directly in terms of operations on longs is
1545              * possible; see "Hacker's Delight" for divide and remainder
1546              * algorithms.
1547              */
1548             return toUnsignedBigInteger(dividend).
1549                 divide(toUnsignedBigInteger(divisor)).longValue();
1550         }
1551     }
1552 
1553     /**
1554      * Returns the unsigned remainder from dividing the first argument
1555      * by the second where each argument and the result is interpreted
1556      * as an unsigned value.
1557      *
1558      * @param dividend the value to be divided
1559      * @param divisor the value doing the dividing
1560      * @return the unsigned remainder of the first argument divided by
1561      * the second argument
1562      * @see #divideUnsigned
1563      * @since 1.8
1564      */
1565     public static long remainderUnsigned(long dividend, long divisor) {
1566         if (dividend > 0 && divisor > 0) { // signed comparisons
1567             return dividend % divisor;
1568         } else {
1569             if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor
1570                 return dividend;
1571             else
1572                 return toUnsignedBigInteger(dividend).
1573                     remainder(toUnsignedBigInteger(divisor)).longValue();
1574         }
1575     }
1576 
1577     // Bit Twiddling
1578 
1579     /**
1580      * The number of bits used to represent a {@code long} value in two's
1581      * complement binary form.
1582      *
1583      * @since 1.5
1584      */
1585     @Native public static final int SIZE = 64;
1586 
1587     /**
1588      * The number of bytes used to represent a {@code long} value in two's
1589      * complement binary form.
1590      *
1591      * @since 1.8
1592      */
1593     public static final int BYTES = SIZE / Byte.SIZE;
1594 
1595     /**
1596      * Returns a {@code long} value with at most a single one-bit, in the
1597      * position of the highest-order ("leftmost") one-bit in the specified
1598      * {@code long} value.  Returns zero if the specified value has no
1599      * one-bits in its two's complement binary representation, that is, if it
1600      * is equal to zero.
1601      *
1602      * @param i the value whose highest one bit is to be computed
1603      * @return a {@code long} value with a single one-bit, in the position
1604      *     of the highest-order one-bit in the specified value, or zero if
1605      *     the specified value is itself equal to zero.
1606      * @since 1.5
1607      */
1608     public static long highestOneBit(long i) {
1609         // HD, Figure 3-1
1610         i |= (i >>  1);
1611         i |= (i >>  2);
1612         i |= (i >>  4);
1613         i |= (i >>  8);
1614         i |= (i >> 16);
1615         i |= (i >> 32);
1616         return i - (i >>> 1);
1617     }
1618 
1619     /**
1620      * Returns a {@code long} value with at most a single one-bit, in the
1621      * position of the lowest-order ("rightmost") one-bit in the specified
1622      * {@code long} value.  Returns zero if the specified value has no
1623      * one-bits in its two's complement binary representation, that is, if it
1624      * is equal to zero.
1625      *
1626      * @param i the value whose lowest one bit is to be computed
1627      * @return a {@code long} value with a single one-bit, in the position
1628      *     of the lowest-order one-bit in the specified value, or zero if
1629      *     the specified value is itself equal to zero.
1630      * @since 1.5
1631      */
1632     public static long lowestOneBit(long i) {
1633         // HD, Section 2-1
1634         return i & -i;
1635     }
1636 
1637     /**
1638      * Returns the number of zero bits preceding the highest-order
1639      * ("leftmost") one-bit in the two's complement binary representation
1640      * of the specified {@code long} value.  Returns 64 if the
1641      * specified value has no one-bits in its two's complement representation,
1642      * in other words if it is equal to zero.
1643      *
1644      * <p>Note that this method is closely related to the logarithm base 2.
1645      * For all positive {@code long} values x:
1646      * <ul>
1647      * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1648      * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1649      * </ul>
1650      *
1651      * @param i the value whose number of leading zeros is to be computed
1652      * @return the number of zero bits preceding the highest-order
1653      *     ("leftmost") one-bit in the two's complement binary representation
1654      *     of the specified {@code long} value, or 64 if the value
1655      *     is equal to zero.
1656      * @since 1.5
1657      */
1658     public static int numberOfLeadingZeros(long i) {
1659         // HD, Figure 5-6
1660          if (i == 0)
1661             return 64;
1662         int n = 1;
1663         int x = (int)(i >>> 32);
1664         if (x == 0) { n += 32; x = (int)i; }
1665         if (x >>> 16 == 0) { n += 16; x <<= 16; }
1666         if (x >>> 24 == 0) { n +=  8; x <<=  8; }
1667         if (x >>> 28 == 0) { n +=  4; x <<=  4; }
1668         if (x >>> 30 == 0) { n +=  2; x <<=  2; }
1669         n -= x >>> 31;
1670         return n;
1671     }
1672 
1673     /**
1674      * Returns the number of zero bits following the lowest-order ("rightmost")
1675      * one-bit in the two's complement binary representation of the specified
1676      * {@code long} value.  Returns 64 if the specified value has no
1677      * one-bits in its two's complement representation, in other words if it is
1678      * equal to zero.
1679      *
1680      * @param i the value whose number of trailing zeros is to be computed
1681      * @return the number of zero bits following the lowest-order ("rightmost")
1682      *     one-bit in the two's complement binary representation of the
1683      *     specified {@code long} value, or 64 if the value is equal
1684      *     to zero.
1685      * @since 1.5
1686      */
1687     public static int numberOfTrailingZeros(long i) {
1688         // HD, Figure 5-14
1689         int x, y;
1690         if (i == 0) return 64;
1691         int n = 63;
1692         y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
1693         y = x <<16; if (y != 0) { n = n -16; x = y; }
1694         y = x << 8; if (y != 0) { n = n - 8; x = y; }
1695         y = x << 4; if (y != 0) { n = n - 4; x = y; }
1696         y = x << 2; if (y != 0) { n = n - 2; x = y; }
1697         return n - ((x << 1) >>> 31);
1698     }
1699 
1700     /**
1701      * Returns the number of one-bits in the two's complement binary
1702      * representation of the specified {@code long} value.  This function is
1703      * sometimes referred to as the <i>population count</i>.
1704      *
1705      * @param i the value whose bits are to be counted
1706      * @return the number of one-bits in the two's complement binary
1707      *     representation of the specified {@code long} value.
1708      * @since 1.5
1709      */
1710      public static int bitCount(long i) {
1711         // HD, Figure 5-2
1712         i = i - ((i >>> 1) & 0x5555555555555555L);
1713         i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1714         i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1715         i = i + (i >>> 8);
1716         i = i + (i >>> 16);
1717         i = i + (i >>> 32);
1718         return (int)i & 0x7f;
1719      }
1720 
1721     /**
1722      * Returns the value obtained by rotating the two's complement binary
1723      * representation of the specified {@code long} value left by the
1724      * specified number of bits.  (Bits shifted out of the left hand, or
1725      * high-order, side reenter on the right, or low-order.)
1726      *
1727      * <p>Note that left rotation with a negative distance is equivalent to
1728      * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1729      * distance)}.  Note also that rotation by any multiple of 64 is a
1730      * no-op, so all but the last six bits of the rotation distance can be
1731      * ignored, even if the distance is negative: {@code rotateLeft(val,
1732      * distance) == rotateLeft(val, distance & 0x3F)}.
1733      *
1734      * @param i the value whose bits are to be rotated left
1735      * @param distance the number of bit positions to rotate left
1736      * @return the value obtained by rotating the two's complement binary
1737      *     representation of the specified {@code long} value left by the
1738      *     specified number of bits.
1739      * @since 1.5
1740      */
1741     public static long rotateLeft(long i, int distance) {
1742         return (i << distance) | (i >>> -distance);
1743     }
1744 
1745     /**
1746      * Returns the value obtained by rotating the two's complement binary
1747      * representation of the specified {@code long} value right by the
1748      * specified number of bits.  (Bits shifted out of the right hand, or
1749      * low-order, side reenter on the left, or high-order.)
1750      *
1751      * <p>Note that right rotation with a negative distance is equivalent to
1752      * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1753      * distance)}.  Note also that rotation by any multiple of 64 is a
1754      * no-op, so all but the last six bits of the rotation distance can be
1755      * ignored, even if the distance is negative: {@code rotateRight(val,
1756      * distance) == rotateRight(val, distance & 0x3F)}.
1757      *
1758      * @param i the value whose bits are to be rotated right
1759      * @param distance the number of bit positions to rotate right
1760      * @return the value obtained by rotating the two's complement binary
1761      *     representation of the specified {@code long} value right by the
1762      *     specified number of bits.
1763      * @since 1.5
1764      */
1765     public static long rotateRight(long i, int distance) {
1766         return (i >>> distance) | (i << -distance);
1767     }
1768 
1769     /**
1770      * Returns the value obtained by reversing the order of the bits in the
1771      * two's complement binary representation of the specified {@code long}
1772      * value.
1773      *
1774      * @param i the value to be reversed
1775      * @return the value obtained by reversing order of the bits in the
1776      *     specified {@code long} value.
1777      * @since 1.5
1778      */
1779     public static long reverse(long i) {
1780         // HD, Figure 7-1
1781         i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1782         i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1783         i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1784         i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1785         i = (i << 48) | ((i & 0xffff0000L) << 16) |
1786             ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1787         return i;
1788     }
1789 
1790     /**
1791      * Returns the signum function of the specified {@code long} value.  (The
1792      * return value is -1 if the specified value is negative; 0 if the
1793      * specified value is zero; and 1 if the specified value is positive.)
1794      *
1795      * @param i the value whose signum is to be computed
1796      * @return the signum function of the specified {@code long} value.
1797      * @since 1.5
1798      */
1799     public static int signum(long i) {
1800         // HD, Section 2-7
1801         return (int) ((i >> 63) | (-i >>> 63));
1802     }
1803 
1804     /**
1805      * Returns the value obtained by reversing the order of the bytes in the
1806      * two's complement representation of the specified {@code long} value.
1807      *
1808      * @param i the value whose bytes are to be reversed
1809      * @return the value obtained by reversing the bytes in the specified
1810      *     {@code long} value.
1811      * @since 1.5
1812      */
1813     public static long reverseBytes(long i) {
1814         i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1815         return (i << 48) | ((i & 0xffff0000L) << 16) |
1816             ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1817     }
1818 
1819     /**
1820      * Adds two {@code long} values together as per the + operator.
1821      *
1822      * @param a the first operand
1823      * @param b the second operand
1824      * @return the sum of {@code a} and {@code b}
1825      * @see java.util.function.BinaryOperator
1826      * @since 1.8
1827      */
1828     public static long sum(long a, long b) {
1829         return a + b;
1830     }
1831 
1832     /**
1833      * Returns the greater of two {@code long} values
1834      * as if by calling {@link Math#max(long, long) Math.max}.
1835      *
1836      * @param a the first operand
1837      * @param b the second operand
1838      * @return the greater of {@code a} and {@code b}
1839      * @see java.util.function.BinaryOperator
1840      * @since 1.8
1841      */
1842     public static long max(long a, long b) {
1843         return Math.max(a, b);
1844     }
1845 
1846     /**
1847      * Returns the smaller of two {@code long} values
1848      * as if by calling {@link Math#min(long, long) Math.min}.
1849      *
1850      * @param a the first operand
1851      * @param b the second operand
1852      * @return the smaller of {@code a} and {@code b}
1853      * @see java.util.function.BinaryOperator
1854      * @since 1.8
1855      */
1856     public static long min(long a, long b) {
1857         return Math.min(a, b);
1858     }
1859 
1860     /** use serialVersionUID from JDK 1.0.2 for interoperability */
1861     @Native private static final long serialVersionUID = 4290774380558885855L;
1862 }