
Java™ Platform Standard Ed. 6 

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java.lang.Object java.lang.Number java.lang.Long
public final class Long
The 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
.
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).
Field Summary  

static long 
MAX_VALUE
A constant holding the maximum value a long can
have, 2^{63}1. 
static long 
MIN_VALUE
A constant holding the minimum value a long can
have, 2^{63}. 
static int 
SIZE
The number of bits used to represent a long value in two's complement binary form. 
static Class<Long> 
TYPE
The Class instance representing the primitive type
long . 
Constructor Summary  

Long(long value)
Constructs a newly allocated Long object that
represents the specified long argument. 

Long(String s)
Constructs a newly allocated Long object that
represents the long value indicated by the
String parameter. 
Method Summary  

static int 
bitCount(long i)
Returns the number of onebits in the two's complement binary representation of the specified long value. 
byte 
byteValue()
Returns the value of this Long as a
byte . 
int 
compareTo(Long anotherLong)
Compares two Long objects numerically. 
static Long 
decode(String nm)
Decodes a String into a Long . 
double 
doubleValue()
Returns the value of this Long as a
double . 
boolean 
equals(Object obj)
Compares this object to the specified object. 
float 
floatValue()
Returns the value of this Long as a
float . 
static Long 
getLong(String nm)
Determines the long value of the system property
with the specified name. 
static Long 
getLong(String nm,
long val)
Determines the long value of the system property
with the specified name. 
static Long 
getLong(String nm,
Long val)
Returns the long value of the system property with
the specified name. 
int 
hashCode()
Returns a hash code for this Long . 
static long 
highestOneBit(long i)
Returns a long value with at most a single onebit, in the position of the highestorder ("leftmost") onebit in the specified long value. 
int 
intValue()
Returns the value of this Long as an
int . 
long 
longValue()
Returns the value of this Long as a
long value. 
static long 
lowestOneBit(long i)
Returns a long value with at most a single onebit, in the position of the lowestorder ("rightmost") onebit in the specified long value. 
static int 
numberOfLeadingZeros(long i)
Returns the number of zero bits preceding the highestorder ("leftmost") onebit in the two's complement binary representation of the specified long value. 
static int 
numberOfTrailingZeros(long i)
Returns the number of zero bits following the lowestorder ("rightmost") onebit in the two's complement binary representation of the specified long value. 
static long 
parseLong(String s)
Parses the string argument as a signed decimal long . 
static long 
parseLong(String s,
int radix)
Parses the string argument as a signed long in the
radix specified by the second argument. 
static long 
reverse(long i)
Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified long value. 
static long 
reverseBytes(long i)
Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified long value. 
static long 
rotateLeft(long i,
int distance)
Returns the value obtained by rotating the two's complement binary representation of the specified long value left by the specified number of bits. 
static long 
rotateRight(long i,
int distance)
Returns the value obtained by rotating the two's complement binary representation of the specified long value right by the specified number of bits. 
short 
shortValue()
Returns the value of this Long as a
short . 
static int 
signum(long i)
Returns the signum function of the specified long value. 
static String 
toBinaryString(long i)
Returns a string representation of the long
argument as an unsigned integer in base 2. 
static String 
toHexString(long i)
Returns a string representation of the long
argument as an unsigned integer in base 16. 
static String 
toOctalString(long i)
Returns a string representation of the long
argument as an unsigned integer in base 8. 
String 
toString()
Returns a String object representing this
Long 's value. 
static String 
toString(long i)
Returns a String object representing the specified
long . 
static String 
toString(long i,
int radix)
Returns a string representation of the first argument in the radix specified by the second argument. 
static Long 
valueOf(long l)
Returns a Long instance representing the specified long value. 
static Long 
valueOf(String s)
Returns a Long object holding the value
of the specified String . 
static Long 
valueOf(String s,
int radix)
Returns a Long object holding the value
extracted from the specified String when parsed
with the radix given by the second argument. 
Methods inherited from class java.lang.Object 

clone, finalize, getClass, notify, notifyAll, wait, wait, wait 
Field Detail 

public static final long MIN_VALUE
long
can
have, 2^{63}.
public static final long MAX_VALUE
long
can
have, 2^{63}1.
public static final Class<Long> TYPE
Class
instance representing the primitive type
long
.
public static final int SIZE
Constructor Detail 

public Long(long value)
Long
object that
represents the specified long
argument.
value
 the value to be represented by the
Long
object.public Long(String s) throws NumberFormatException
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
.parseLong(java.lang.String, int)
Method Detail 

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:
These are0123456789abcdefghijklmnopqrstuvwxyz
'\u0030'
through
'\u0039'
and '\u0061'
through
'\u007a'
. If radix
is
N, then the first N of these characters
are used as radixN 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.
Character.MAX_RADIX
,
Character.MIN_RADIX
public static String toHexString(long i)
long
argument as an unsigned integer in base 16.
The unsigned long
value is the argument plus
2^{64} 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 0
s. 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:
These are the characters0123456789abcdef
'\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()
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
2^{64} 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
0
s.
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:
These are the characters01234567
'\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
2^{64} 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
0
s. 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 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. 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 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'
) provided that the
string is longer than length 1.
long
.
Examples:
parseLong("0", 10) returns 0L parseLong("473", 10) returns 473L 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(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. 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 parsed
long
represented by the argument in
decimal.
NumberFormatException
 if the string does not contain a
parsable long
.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:
new Long(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:
new Long(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(long)
, as this method is likely to yield
significantly better space and time performance by caching
frequently requested values.
l
 a long value.
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 defined in §3.10.1 of the Java Language Specification.
 DecodableString:
 Sign_{opt} DecimalNumeral
 Sign_{opt}
0x
HexDigits Sign_{opt}
0X
HexDigits Sign_{opt}
#
HexDigits Sign_{opt}
0
OctalDigits
 Sign:

The sequence of characters following an (optional) negative
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
.parseLong(String, int)
public byte byteValue()
Long
as a
byte
.
byteValue
in class Number
byte
.public short shortValue()
Long
as a
short
.
shortValue
in class Number
short
.public int intValue()
Long
as an
int
.
intValue
in class Number
int
.public long longValue()
Long
as a
long
value.
longValue
in class Number
long
.public float floatValue()
Long
as a
float
.
floatValue
in class Number
float
.public double doubleValue()
Long
as a
double
.
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.
toString
in class Object
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))
hashCode
in class Object
Object.equals(java.lang.Object)
,
Hashtable
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.
equals
in class Object
obj
 the object to compare with.
true
if the objects are the same;
false
otherwise.Object.hashCode()
,
Hashtable
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 and a Long
object
representing this value is returned. Details of possible
numeric formats can be found with the definition of
getProperty
.
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.System.getProperty(java.lang.String)
,
System.getProperty(java.lang.String, java.lang.String)
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 and a Long
object
representing this value is returned. Details of possible
numeric formats can be found with the definition of
getProperty
.
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, new Long(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) ? new Long(val) : result;
Long
object when
the default value is not needed.
nm
 property name.val
 default value.
Long
value of the property.System.getProperty(java.lang.String)
,
System.getProperty(java.lang.String, java.lang.String)
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
Long.decode
method, and a Long
object
representing this value is returned.
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.System.getProperty(java.lang.String)
,
System.getProperty(java.lang.String, java.lang.String)
,
decode(java.lang.String)
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 long highestOneBit(long i)
public static long lowestOneBit(long i)
public static int numberOfLeadingZeros(long i)
Note that this method is closely related to the logarithm base 2. For all positive long values x:
public static int numberOfTrailingZeros(long i)
public static int bitCount(long i)
public static long rotateLeft(long i, int distance)
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 noop, 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).
public static long rotateRight(long i, int distance)
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 noop, 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).
public static long reverse(long i)
public static int signum(long i)
public static long reverseBytes(long i)

Java™ Platform Standard Ed. 6 

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