Serializable, Comparable<Long>, Constable, ConstantDesc
public final class Long extends Number implements Comparable<Long>, Constable, ConstantDesc
Long class wraps a value of the primitive type 
 long in an object. An object of type Long contains a single field whose type is long.  In addition, this class provides several methods for converting a long to a String and a String to a 
 long, as well as other constants and methods useful when dealing with a long. 
This is a value-based class; programmers should treat instances that are equal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail.
Implementation note: The implementations of the "bit twiddling" methods (such as highestOneBit and numberOfTrailingZeros) are based on material from Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002).
| Modifier and Type | Field | Description | 
|---|---|---|
| static final int | BYTES | The number of bytes used to represent a  longvalue in two's complement binary form. | 
| static final long | MAX_VALUE | A constant holding the maximum value a  longcan have, 263-1. | 
| static final long | MIN_VALUE | A constant holding the minimum value a  longcan have, -263. | 
| static final int | SIZE | The number of bits used to represent a  longvalue in two's complement binary form. | 
| static final Class | TYPE | The  Classinstance representing the primitive typelong. | 
| Constructor | Description | 
|---|---|
| Long | 
Deprecated, for removal: This API element is subject to removal in a future version.  It is rarely appropriate to use this constructor. | 
| Long | 
Deprecated, for removal: This API element is subject to removal in a future version.  It is rarely appropriate to use this constructor. | 
| Modifier and Type | Method | Description | 
|---|---|---|
| static int | bitCount | Returns the number of one-bits in the two's complement binary representation of the specified  longvalue. | 
| byte | byteValue() | Returns the value of this  Longas abyteafter a narrowing primitive conversion. | 
| static int | compare | Compares two  longvalues numerically. | 
| int | compareTo | Compares two  Longobjects numerically. | 
| static int | compareUnsigned | Compares two  longvalues numerically treating the values as unsigned. | 
| static long | compress | Returns the value obtained by compressing the bits of the specified  longvalue,i, in accordance with the specified bit mask. | 
| static Long | decode | Decodes a  Stringinto aLong. | 
| Optional | describeConstable() | Returns an  Optionalcontaining the nominal descriptor for this instance, which is the instance itself. | 
| static long | divideUnsigned | Returns the unsigned quotient of dividing the first argument by the second where each argument and the result is interpreted as an unsigned value. | 
| double | doubleValue() | Returns the value of this  Longas adoubleafter a widening primitive conversion. | 
| boolean | equals | Compares this object to the specified object. | 
| static long | expand | Returns the value obtained by expanding the bits of the specified  longvalue,i, in accordance with the specified bit mask. | 
| float | floatValue() | Returns the value of this  Longas afloatafter a widening primitive conversion. | 
| static Long | getLong | Determines the  longvalue of the system property with the specified name. | 
| static Long | getLong | Determines the  longvalue of the system property with the specified name. | 
| static Long | getLong | Returns the  longvalue of the system property with the specified name. | 
| int | hashCode() | Returns a hash code for this  Long. | 
| static int | hashCode | Returns a hash code for a  longvalue; compatible withLong.hashCode(). | 
| static long | highestOneBit | Returns a  longvalue with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specifiedlongvalue. | 
| int | intValue() | Returns the value of this  Longas anintafter a narrowing primitive conversion. | 
| long | longValue() | Returns the value of this  Longas alongvalue. | 
| static long | lowestOneBit | Returns a  longvalue with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specifiedlongvalue. | 
| static long | max | Returns the greater of two  longvalues as if by callingMath.max. | 
| static long | min | Returns the smaller of two  longvalues as if by callingMath.min. | 
| static int | numberOfLeadingZeros | Returns the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specified  longvalue. | 
| static int | numberOfTrailingZeros | Returns the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specified  longvalue. | 
| static long | parseLong | Parses the  CharSequenceargument as a signedlongin the specifiedradix, beginning at the specifiedbeginIndexand extending toendIndex - 1. | 
| static long | parseLong | Parses the string argument as a signed decimal  long. | 
| static long | parseLong | Parses the string argument as a signed  longin the radix specified by the second argument. | 
| static long | parseUnsignedLong | Parses the  CharSequenceargument as an unsignedlongin the specifiedradix, beginning at the specifiedbeginIndexand extending toendIndex - 1. | 
| static long | parseUnsignedLong | Parses the string argument as an unsigned decimal  long. | 
| static long | parseUnsignedLong | Parses the string argument as an unsigned  longin the radix specified by the second argument. | 
| static long | remainderUnsigned | Returns the unsigned remainder from dividing the first argument by the second where each argument and the result is interpreted as an unsigned value. | 
| Long | resolveConstantDesc | Resolves this instance as a  ConstantDesc, the result of which is the instance itself. | 
| static long | reverse | Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified  longvalue. | 
| static long | reverseBytes | Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified  longvalue. | 
| static long | rotateLeft | Returns the value obtained by rotating the two's complement binary representation of the specified  longvalue left by the specified number of bits. | 
| static long | rotateRight | Returns the value obtained by rotating the two's complement binary representation of the specified  longvalue right by the specified number of bits. | 
| short | shortValue() | Returns the value of this  Longas ashortafter a narrowing primitive conversion. | 
| static int | signum | Returns the signum function of the specified  longvalue. | 
| static long | sum | Adds two  longvalues together as per the + operator. | 
| static String | toBinaryString | Returns a string representation of the  longargument as an unsigned integer in base 2. | 
| static String | toHexString | Returns a string representation of the  longargument as an unsigned integer in base 16. | 
| static String | toOctalString | Returns a string representation of the  longargument as an unsigned integer in base 8. | 
| String | toString() | Returns a  Stringobject representing thisLong's value. | 
| static String | toString | Returns a  Stringobject representing the specifiedlong. | 
| static String | toString | Returns a string representation of the first argument in the radix specified by the second argument. | 
| static String | toUnsignedString | Returns a string representation of the argument as an unsigned decimal value. | 
| static String | toUnsignedString | Returns a string representation of the first argument as an unsigned integer value in the radix specified by the second argument. | 
| static Long | valueOf | Returns a  Longinstance representing the specifiedlongvalue. | 
| static Long | valueOf | Returns a  Longobject holding the value of the specifiedString. | 
| static Long | valueOf | Returns a  Longobject holding the value extracted from the specifiedStringwhen parsed with the radix given by the second argument. | 
@Native public static final long MIN_VALUE
long can have, -263.@Native public static final long MAX_VALUE
long can have, 263-1.public static final Class<Long> TYPE
Class instance representing the primitive type long.@Native public static final int SIZE
long value in two's complement binary form.public static final int BYTES
long value in two's complement binary form.@Deprecated(since="9", forRemoval=true) public Long(long value)
valueOf(long) is generally a better choice, as it is likely to yield significantly better space and time performance.Long object that represents the specified long argument.value - the value to be represented by the Long object.@Deprecated(since="9", forRemoval=true) public Long(String s) throws NumberFormatException
parseLong(String) to convert a string to a long primitive, or use valueOf(String) to convert a string to a Long object.Long object that represents the long value indicated by the String parameter. The string is converted to a long value in exactly the manner used by the parseLong method for radix 10.s - the String to be converted to a Long.NumberFormatException - if the String does not contain a parsable long.public static String toString(long i, int radix)
If the radix is smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX, then the radix 10 is used instead. 
If the first argument is negative, the first element of the result is the ASCII minus sign '-' ('\u002d'). If the first argument is not negative, no sign character appears in the result. 
The remaining characters of the result represent the magnitude of the first argument. If the magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the magnitude will not be the zero character. The following ASCII characters are used as digits: 
 0123456789abcdefghijklmnopqrstuvwxyz  These are '\u0030' through '\u0039' and '\u0061' through '\u007a'. If radix is N, then the first N of these characters are used as radix-N digits in the order shown. Thus, the digits for hexadecimal (radix 16) are 0123456789abcdef. If uppercase letters are desired, the String.toUpperCase() method may be called on the result:  Long.toString(n, 16).toUpperCase() 
i - a long to be converted to a string.radix - the radix to use in the string representation.public static String toUnsignedString(long i, int radix)
If the radix is smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX, then the radix 10 is used instead. 
Note that since the first argument is treated as an unsigned value, no leading sign character is printed.
If the magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the magnitude will not be the zero character. 
The behavior of radixes and the characters used as digits are the same as toString.
i - an integer to be converted to an unsigned string.radix - the radix to use in the string representation.public static String toHexString(long i)
long argument as an unsigned integer in base 16. The unsigned long value is the argument plus 264 if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in hexadecimal (base 16) with no extra leading 0s. 
The value of the argument can be recovered from the returned string s by calling Long.parseUnsignedLong(s,
 16). 
If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The following characters are used as hexadecimal digits: 
 0123456789abcdef  These are the characters '\u0030' through '\u0039' and '\u0061' through '\u0066'. If uppercase letters are desired, the String.toUpperCase() method may be called on the result:  Long.toHexString(n).toUpperCase() 
HexFormat class provides formatting and parsing of byte arrays and primitives to return a string or adding to an Appendable. HexFormat formats and parses uppercase or lowercase hexadecimal characters, with leading zeros and for byte arrays includes for each byte a delimiter, prefix, and suffix.i - a long to be converted to a string.long value represented by the argument in hexadecimal (base 16).public static String toOctalString(long i)
long argument as an unsigned integer in base 8. The unsigned long value is the argument plus 264 if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in octal (base 8) with no extra leading 0s. 
The value of the argument can be recovered from the returned string s by calling Long.parseUnsignedLong(s,
 8). 
If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The following characters are used as octal digits: 
 01234567  These are the characters '\u0030' through '\u0037'.i - a long to be converted to a string.long value represented by the argument in octal (base 8).public static String toBinaryString(long i)
long argument as an unsigned integer in base 2. The unsigned long value is the argument plus 264 if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in binary (base 2) with no extra leading 0s. 
The value of the argument can be recovered from the returned string s by calling Long.parseUnsignedLong(s,
 2). 
If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The characters '0' ('\u0030') and 
 '1' ('\u0031') are used as binary digits.
i - a long to be converted to a string.long value represented by the argument in binary (base 2).public static String toString(long i)
String object representing the specified long. The argument is converted to signed decimal representation and returned as a string, exactly as if the argument and the radix 10 were given as arguments to the toString(long, int) method.i - a long to be converted.public static String toUnsignedString(long i)
toUnsignedString(long, int) method.i - an integer to be converted to an unsigned string.public static long parseLong(String s, int radix) throws NumberFormatException
long in the radix specified by the second argument. The characters in the string must all be digits of the specified radix (as determined by whether Character.digit(char, int) returns a nonnegative value), except that the first character may be an ASCII minus sign '-' ('\u002D') to indicate a negative value or an ASCII plus sign '+' ('\u002B') to indicate a positive value. The resulting long value is returned. Note that neither the character L ('\u004C') nor l ('\u006C') is permitted to appear at the end of the string as a type indicator, as would be permitted in Java programming language source code - except that either L or l may appear as a digit for a radix greater than or equal to 22. 
An exception of type NumberFormatException is thrown if any of the following situations occurs: 
null or is a string of length zero. radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX. '-' ('\u002d') or plus sign 
 '+' ('\u002B') provided that the string is longer than length 1. long. Examples:
 parseLong("0", 10) returns 0L
 parseLong("473", 10) returns 473L
 parseLong("+42", 10) returns 42L
 parseLong("-0", 10) returns 0L
 parseLong("-FF", 16) returns -255L
 parseLong("1100110", 2) returns 102L
 parseLong("99", 8) throws a NumberFormatException
 parseLong("Hazelnut", 10) throws a NumberFormatException
 parseLong("Hazelnut", 36) returns 1356099454469L
 s - the String containing the long representation to be parsed.radix - the radix to be used while parsing s.long represented by the string argument in the specified radix.NumberFormatException - if the string does not contain a parsable long.public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix) throws NumberFormatException
CharSequence argument as a signed long in the specified radix, beginning at the specified beginIndex and extending to endIndex - 1. The method does not take steps to guard against the CharSequence being mutated while parsing.
s - the CharSequence containing the long representation to be parsedbeginIndex - the beginning index, inclusive.endIndex - the ending index, exclusive.radix - the radix to be used while parsing s.long represented by the subsequence in the specified radix.NullPointerException - if s is null.IndexOutOfBoundsException - if beginIndex is negative, or if beginIndex is greater than endIndex or if endIndex is greater than s.length().NumberFormatException - if the CharSequence does not contain a parsable long in the specified radix, or if radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX.public static long parseLong(String s) throws NumberFormatException
long. The characters in the string must all be decimal digits, except that the first character may be an ASCII minus sign '-' (\u002D') to indicate a negative value or an ASCII plus sign '+' ('\u002B') to indicate a positive value. The resulting long value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseLong(java.lang.String, int) method. Note that neither the character L ('\u004C') nor l ('\u006C') is permitted to appear at the end of the string as a type indicator, as would be permitted in Java programming language source code.
s - a String containing the long representation to be parsedlong represented by the argument in decimal.NumberFormatException - if the string does not contain a parsable long.public static long parseUnsignedLong(String s, int radix) throws NumberFormatException
long in the radix specified by the second argument. An unsigned integer maps the values usually associated with negative numbers to positive numbers larger than MAX_VALUE. The characters in the string must all be digits of the specified radix (as determined by whether Character.digit(char, int) returns a nonnegative value), except that the first character may be an ASCII plus sign '+' ('\u002B'). The resulting integer value is returned. An exception of type NumberFormatException is thrown if any of the following situations occurs: 
null or is a string of length zero. Character.MIN_RADIX or larger than Character.MAX_RADIX. '+' ('\u002B') provided that the string is longer than length 1. long, 264-1. s - the String containing the unsigned integer representation to be parsedradix - the radix to be used while parsing s.long represented by the string argument in the specified radix.NumberFormatException - if the String does not contain a parsable long.public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix) throws NumberFormatException
CharSequence argument as an unsigned long in the specified radix, beginning at the specified beginIndex and extending to endIndex - 1. The method does not take steps to guard against the CharSequence being mutated while parsing.
s - the CharSequence containing the unsigned long representation to be parsedbeginIndex - the beginning index, inclusive.endIndex - the ending index, exclusive.radix - the radix to be used while parsing s.long represented by the subsequence in the specified radix.NullPointerException - if s is null.IndexOutOfBoundsException - if beginIndex is negative, or if beginIndex is greater than endIndex or if endIndex is greater than s.length().NumberFormatException - if the CharSequence does not contain a parsable unsigned long in the specified radix, or if radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX.public static long parseUnsignedLong(String s) throws NumberFormatException
long. The characters in the string must all be decimal digits, except that the first character may be an ASCII plus sign 
 '+' ('\u002B'). The resulting integer value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseUnsignedLong(java.lang.String, int) method.s - a String containing the unsigned long representation to be parsedlong value represented by the decimal string argumentNumberFormatException - if the string does not contain a parsable unsigned integer.public static Long valueOf(String s, int radix) throws NumberFormatException
Long object holding the value extracted from the specified String when parsed with the radix given by the second argument. The first argument is interpreted as representing a signed long in the radix specified by the second argument, exactly as if the arguments were given to the parseLong(java.lang.String, int) method. The result is a Long object that represents the long value specified by the string. In other words, this method returns a Long object equal to the value of: 
 Long.valueOf(Long.parseLong(s, radix)) 
s - the string to be parsedradix - the radix to be used in interpreting s
Long object holding the value represented by the string argument in the specified radix.NumberFormatException - If the String does not contain a parsable long.public static Long valueOf(String s) throws NumberFormatException
Long object holding the value of the specified String. The argument is interpreted as representing a signed decimal long, exactly as if the argument were given to the parseLong(java.lang.String) method. The result is a Long object that represents the integer value specified by the string. In other words, this method returns a Long object equal to the value of: 
 Long.valueOf(Long.parseLong(s)) 
s - the string to be parsed.Long object holding the value represented by the string argument.NumberFormatException - If the string cannot be parsed as a long.public static Long valueOf(long l)
Long instance representing the specified long value. If a new Long instance is not required, this method should generally be used in preference to the constructor Long(long), as this method is likely to yield significantly better space and time performance by caching frequently requested values. This method will always cache values in the range -128 to 127, inclusive, and may cache other values outside of this range.l - a long value.Long instance representing l.public static Long decode(String nm) throws NumberFormatException
String into a Long. Accepts decimal, hexadecimal, and octal numbers given by the following grammar: DecimalNumeral, HexDigits, and OctalDigits are as defined in section 3.10.1 of The Java Language Specification, except that underscores are not accepted between digits.
- DecodableString:
- Signopt DecimalNumeral
- Signopt
0xHexDigits- Signopt
0XHexDigits- Signopt
#HexDigits- Signopt
0OctalDigits- Sign:
-
+
The sequence of characters following an optional sign and/or radix specifier ("0x", "0X", "#", or leading zero) is parsed as by the 
 Long.parseLong method with the indicated radix (10, 16, or 8). This sequence of characters must represent a positive value or a NumberFormatException will be thrown. The result is negated if first character of the specified String is the minus sign. No whitespace characters are permitted in the String.
nm - the String to decode.Long object holding the long value represented by nm
NumberFormatException - if the String does not contain a parsable long.public byte byteValue()
Long as a byte after a narrowing primitive conversion.byteValue in class Number
byte.public short shortValue()
Long as a short after a narrowing primitive conversion.shortValue in class Number
short.public int intValue()
Long as an int after a narrowing primitive conversion.intValue in class Number
int.public long longValue()
Long as a long value.public float floatValue()
Long as a float after a widening primitive conversion.floatValue in class Number
float.public double doubleValue()
Long as a double after a widening primitive conversion.doubleValue in class Number
double.public String toString()
String object representing this Long's value. The value is converted to signed decimal representation and returned as a string, exactly as if the long value were given as an argument to the toString(long) method.public int hashCode()
Long. The result is the exclusive OR of the two halves of the primitive long value held by this Long object. That is, the hashcode is the value of the expression:  (int)(this.longValue()^(this.longValue()>>>32)) 
public static int hashCode(long value)
long value; compatible with Long.hashCode().value - the value to hashlong value.public boolean equals(Object obj)
true if and only if the argument is not null and is a Long object that contains the same long value as this object.public static Long getLong(String nm)
long value of the system property with the specified name. The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String) method. The string value of this property is then interpreted as a 
 long value using the grammar supported by decode and a Long object representing this value is returned. 
If there is no property with the specified name, if the specified name is empty or null, or if the property does not have the correct numeric format, then null is returned. 
In other words, this method returns a Long object equal to the value of: 
 getLong(nm, null) 
nm - property name.Long value of the property.SecurityException - for the same reasons as System.getProperty
public static Long getLong(String nm, long val)
long value of the system property with the specified name. The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String) method. The string value of this property is then interpreted as a 
 long value using the grammar supported by decode and a Long object representing this value is returned. 
The second argument is the default value. A Long object that represents the value of the second argument is returned if there is no property of the specified name, if the property does not have the correct numeric format, or if the specified name is empty or null. 
In other words, this method returns a Long object equal to the value of: 
 getLong(nm, Long.valueOf(val))  but in practice it may be implemented in a manner such as: to avoid the unnecessary allocation of aLong result = getLong(nm, null); return (result == null) ? Long.valueOf(val) : result;
Long object when the default value is not needed.nm - property name.val - default value.Long value of the property.SecurityException - for the same reasons as System.getProperty
public static Long getLong(String nm, Long val)
long value of the system property with the specified name. The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String) method. The string value of this property is then interpreted as a long value, as per the decode method, and a Long object representing this value is returned; in summary: 0x or the ASCII character #, not followed by a minus sign, then the rest of it is parsed as a hexadecimal integer exactly as for the method valueOf(java.lang.String, int) with radix 16. 0 followed by another character, it is parsed as an octal integer exactly as by the method valueOf(java.lang.String, int) with radix 8. valueOf(java.lang.String, int) with radix 10. Note that, in every case, neither L ('\u004C') nor l ('\u006C') is permitted to appear at the end of the property value as a type indicator, as would be permitted in Java programming language source code. 
The second argument is the default value. The default value is returned if there is no property of the specified name, if the property does not have the correct numeric format, or if the specified name is empty or null.
nm - property name.val - default value.Long value of the property.SecurityException - for the same reasons as System.getProperty
public int compareTo(Long anotherLong)
Long objects numerically.compareTo in interface Comparable<Long>
anotherLong - the Long to be compared.0 if this Long is equal to the argument Long; a value less than 0 if this Long is numerically less than the argument Long; and a value greater than 0 if this Long is numerically greater than the argument Long (signed comparison).public static int compare(long x, long y)
long values numerically. The value returned is identical to what would be returned by: 
    Long.valueOf(x).compareTo(Long.valueOf(y))
 
x - the first long to comparey - the second long to compare0 if x == y; a value less than 0 if x < y; and a value greater than 0 if x > y
public static int compareUnsigned(long x, long y)
long values numerically treating the values as unsigned.x - the first long to comparey - the second long to compare0 if x == y; a value less than 0 if x < y as unsigned values; and a value greater than 0 if x > y as unsigned valuespublic static long divideUnsigned(long dividend, long divisor)
Note that in two's complement arithmetic, the three other basic arithmetic operations of add, subtract, and multiply are bit-wise identical if the two operands are regarded as both being signed or both being unsigned. Therefore separate 
 addUnsigned, etc. methods are not provided.
dividend - the value to be divideddivisor - the value doing the dividingpublic static long remainderUnsigned(long dividend, long divisor)
dividend - the value to be divideddivisor - the value doing the dividingpublic static long highestOneBit(long i)
long value with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specified long value. Returns zero if the specified value has no one-bits in its two's complement binary representation, that is, if it is equal to zero.i - the value whose highest one bit is to be computedlong value with a single one-bit, in the position of the highest-order one-bit in the specified value, or zero if the specified value is itself equal to zero.public static long lowestOneBit(long i)
long value with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specified long value. Returns zero if the specified value has no one-bits in its two's complement binary representation, that is, if it is equal to zero.i - the value whose lowest one bit is to be computedlong value with a single one-bit, in the position of the lowest-order one-bit in the specified value, or zero if the specified value is itself equal to zero.public static int numberOfLeadingZeros(long i)
long value. Returns 64 if the specified value has no one-bits in its two's complement representation, in other words if it is equal to zero. Note that this method is closely related to the logarithm base 2. For all positive long values x: 
63 - numberOfLeadingZeros(x) 64 - numberOfLeadingZeros(x - 1) i - the value whose number of leading zeros is to be computedlong value, or 64 if the value is equal to zero.public static int numberOfTrailingZeros(long i)
long value. Returns 64 if the specified value has no one-bits in its two's complement representation, in other words if it is equal to zero.i - the value whose number of trailing zeros is to be computedlong value, or 64 if the value is equal to zero.public static int bitCount(long i)
long value. This function is sometimes referred to as the population count.i - the value whose bits are to be countedlong value.public static long rotateLeft(long i, int distance)
long value left by the specified number of bits. (Bits shifted out of the left hand, or high-order, side reenter on the right, or low-order.) Note that left rotation with a negative distance is equivalent to right rotation: rotateLeft(val, -distance) == rotateRight(val,
 distance). Note also that rotation by any multiple of 64 is a no-op, so all but the last six bits of the rotation distance can be ignored, even if the distance is negative: rotateLeft(val,
 distance) == rotateLeft(val, distance & 0x3F).
i - the value whose bits are to be rotated leftdistance - the number of bit positions to rotate leftlong value left by the specified number of bits.public static long rotateRight(long i, int distance)
long value right by the specified number of bits. (Bits shifted out of the right hand, or low-order, side reenter on the left, or high-order.) Note that right rotation with a negative distance is equivalent to left rotation: rotateRight(val, -distance) == rotateLeft(val,
 distance). Note also that rotation by any multiple of 64 is a no-op, so all but the last six bits of the rotation distance can be ignored, even if the distance is negative: rotateRight(val,
 distance) == rotateRight(val, distance & 0x3F).
i - the value whose bits are to be rotated rightdistance - the number of bit positions to rotate rightlong value right by the specified number of bits.public static long reverse(long i)
long value.i - the value to be reversedlong value.public static long compress(long i, long mask)
long value, i, in accordance with the specified bit mask.  For each one-bit value mb of the mask, from least significant to most significant, the bit value of i at the same bit location as mb is assigned to the compressed value contiguously starting from the least significant bit location. All the upper remaining bits of the compressed value are set to zero.
// Compressing drink to food
compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
0xFF00FFF0 selects hexadecimal digits at positions 1, 2, 3, 6 and 7 of 0xCAFEBABE. The selected digits occur in the resulting compressed value contiguously from digit position 0 in the same order.  The following identities all return true and are helpful to understand the behaviour of compress: 
// Returns 1 if the bit at position n is one
compress(x, 1L << n) == (x >> n & 1)
// Logical shift right
compress(x, -1L << n) == x >>> n
// Any bits not covered by the mask are ignored
compress(x, m) == compress(x & m, m)
// Compressing a value by itself
compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
// Expanding then compressing with the same mask
compress(expand(x, m), m) == x & compress(m, m)
The Sheep And Goats (SAG) operation (see Hacker's Delight, section 7.7) can be implemented as follows:
long compressLeft(long i, long mask) {
    // This implementation follows the description in Hacker's Delight which
    // is informative. A more optimal implementation is:
    //   Long.compress(i, mask) << -Long.bitCount(mask)
    return Long.reverse(
        Long.compress(Long.reverse(i), Long.reverse(mask)));
}
long sag(long i, long mask) {
    return compressLeft(i, mask) | Long.compress(i, ~mask);
}
// Separate the sheep from the goats
sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
i - the value whose bits are to be compressedmask - the bit maskpublic static long expand(long i, long mask)
long value, i, in accordance with the specified bit mask.  For each one-bit value mb of the mask, from least significant to most significant, the next contiguous bit value of i starting at the least significant bit is assigned to the expanded value at the same bit location as mb. All other remaining bits of the expanded value are set to zero.
expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
0xFF00FFF0 selects the first five hexadecimal digits of 0x0000CABAB. The selected digits occur in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.  The following identities all return true and are helpful to understand the behaviour of expand: 
// Logically shift right the bit at position 0
expand(x, 1L << n) == (x & 1) << n
// Logically shift right
expand(x, -1L << n) == x << n
// Expanding all bits returns the mask
expand(-1L, m) == m
// Any bits not covered by the mask are ignored
expand(x, m) == expand(x, m) & m
// Compressing then expanding with the same mask
expand(compress(x, m), m) == x & m
 The select operation for determining the position of the one-bit with index n in a long value can be implemented as follows: 
long select(long i, long n) {
    // the one-bit in i (the mask) with index n
    long nthBit = Long.expand(1L << n, i);
    // the bit position of the one-bit with index n
    return Long.numberOfTrailingZeros(nthBit);
}
// The one-bit with index 0 is at bit position 1
select(0b10101010_10101010, 0) == 1
// The one-bit with index 3 is at bit position 7
select(0b10101010_10101010, 3) == 7
i - the value whose bits are to be expandedmask - the bit maskpublic static int signum(long i)
long value. (The return value is -1 if the specified value is negative; 0 if the specified value is zero; and 1 if the specified value is positive.)i - the value whose signum is to be computedlong value.public static long reverseBytes(long i)
long value.i - the value whose bytes are to be reversedlong value.public static long sum(long a, long b)
long values together as per the + operator.a - the first operandb - the second operanda and b
public static long max(long a, long b)
long values as if by calling Math.max.a - the first operandb - the second operanda and b
public static long min(long a, long b)
long values as if by calling Math.min.a - the first operandb - the second operanda and b
public Optional<Long> describeConstable()
Optional containing the nominal descriptor for this instance, which is the instance itself.describeConstable in interface Constable
Optional describing the Long instancepublic Long resolveConstantDesc(MethodHandles.Lookup lookup)
ConstantDesc, the result of which is the instance itself.resolveConstantDesc in interface ConstantDesc
lookup - ignored
    © 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
    https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/Long.html