public final class Double extends Number implements Comparable<Double>
Double
class wraps a value of the primitive type double
in an object. An
object of type Double
contains a single field whose type is double
.
In addition, this class provides several methods for converting a double
to a
String
and a String
to a double
, as well as other constants and methods
useful when dealing with a double
.
Modifier and Type  Field and Description 

static int 
MAX_EXPONENT
Maximum exponent a finite
double variable may have. 
static double 
MAX_VALUE
A constant holding the largest positive finite value of type
double ,
(22^{52})·2^{1023}. 
static int 
MIN_EXPONENT
Minimum exponent a normalized
double variable may have. 
static double 
MIN_NORMAL
A constant holding the smallest positive normal value of type
double ,
2^{1022}. 
static double 
MIN_VALUE
A constant holding the smallest positive nonzero value of type
double ,
2^{1074}. 
static double 
NaN
A constant holding a NotaNumber (NaN) value of type
double . 
static double 
NEGATIVE_INFINITY
A constant holding the negative infinity of type
double . 
static double 
POSITIVE_INFINITY
A constant holding the positive infinity of type
double . 
static int 
SIZE
The number of bits used to represent a
double value. 
Constructor and Description 

Double(double value)
Constructs a newly allocated
Double object that represents the primitive
double argument. 
Double(String s)
Constructs a newly allocated
Double object that represents the floatingpoint value
of type double represented by the string. 
Modifier and Type  Method and Description 

byte 
byteValue()
Returns the value of this
Double as a byte (by casting to a byte ). 
static int 
compare(double d1,
double d2)
Compares the two specified
double values. 
int 
compareTo(Double anotherDouble)
Compares two
Double objects numerically. 
static long 
doubleToLongBits(double value)
Returns a representation of the specified floatingpoint value according to the IEEE 754
floatingpoint "double format" bit layout.

static long 
doubleToRawLongBits(double value)
Returns a representation of the specified floatingpoint value according to the IEEE 754
floatingpoint "double format" bit layout, preserving NotaNumber (NaN) values.

double 
doubleValue()
Returns the
double value of this Double object. 
boolean 
equals(Object obj)
Compares this object against the specified object.

float 
floatValue()
Returns the
float value of this Double object. 
int 
hashCode()
Returns a hash code for this
Double object. 
int 
intValue()
Returns the value of this
Double as an int (by casting to type int ). 
boolean 
isInfinite()
Returns
true if this Double value is infinitely large in magnitude,
false otherwise. 
static boolean 
isInfinite(double v)
Returns
true if the specified number is infinitely large in magnitude, false
otherwise. 
boolean 
isNaN()
Returns
true if this Double value is a NotaNumber (NaN), false
otherwise. 
static boolean 
isNaN(double v)
Returns
true if the specified number is a NotaNumber (NaN) value, false
otherwise. 
static double 
longBitsToDouble(long bits)
Returns the
double value corresponding to a given bit representation. 
long 
longValue()
Returns the value of this
Double as a long (by casting to type long ). 
static double 
parseDouble(String s)
Returns a new
double initialized to the value represented by the specified
String , as performed by the valueOf method of class Double . 
short 
shortValue()
Returns the value of this
Double as a short (by casting to a short ). 
String 
toString()
Returns a string representation of this
Double object. 
static String 
toString(double d)
Returns a string representation of the
double argument. 
static Double 
valueOf(double d)
Returns a
Double instance representing the specified double value. 
static Double 
valueOf(String s)
Returns a
Double object holding the double value represented by the argument
string s . 
public static final int MAX_EXPONENT
double
variable may have. It is equal to the value returned
by Math.getExponent(Double.MAX_VALUE)
.public static final double MAX_VALUE
double
,
(22^{52})·2^{1023}. It is equal to the hexadecimal floatingpoint
literal 0x1.fffffffffffffP+1023
and also equal to
Double.longBitsToDouble(0x7fefffffffffffffL)
.public static final int MIN_EXPONENT
double
variable may have. It is equal to the value
returned by Math.getExponent(Double.MIN_NORMAL)
.public static final double MIN_NORMAL
double
,
2^{1022}. It is equal to the hexadecimal floatingpoint literal 0x1.0p1022
and also equal to Double.longBitsToDouble(0x0010000000000000L)
.public static final double MIN_VALUE
double
,
2^{1074}. It is equal to the hexadecimal floatingpoint literal
0x0.0000000000001P1022
and also equal to Double.longBitsToDouble(0x1L)
.public static final double NaN
double
. It is equivalent to the
value returned by Double.longBitsToDouble(0x7ff8000000000000L)
.public static final double NEGATIVE_INFINITY
double
. It is equal to the value
returned by Double.longBitsToDouble(0xfff0000000000000L)
.public static final double POSITIVE_INFINITY
double
. It is equal to the value
returned by Double.longBitsToDouble(0x7ff0000000000000L)
.public static final int SIZE
double
value.public Double(double value)
Double
object that represents the primitive
double
argument.value
 the value to be represented by the Double
.public Double(String s) throws NumberFormatException
Double
object that represents the floatingpoint value
of type double
represented by the string. The string is converted to a double
value as if by the valueOf
method.s
 a string to be converted to a Double
.NumberFormatException
 if the string does not contain a parsable number.valueOf(java.lang.String)
public static int compare(double d1, double d2)
double
values. The sign of the integer value returned is
the same as that of the integer that would be returned by the call:
new Double(d1).compareTo(new Double(d2))
d1
 the first double
to compared2
 the second double
to compare0
if d1
is numerically equal to d2
; a value less
than 0
if d1
is numerically less than d2
; and a value greater
than 0
if d1
is numerically greater than d2
.public static long doubleToLongBits(double value)
Bit 63 (the bit that is selected by the mask 0x8000000000000000L
) represents the sign
of the floatingpoint number. Bits 6252 (the bits that are selected by the mask
0x7ff0000000000000L
) represent the exponent. Bits 510 (the bits that are selected by
the mask 0x000fffffffffffffL
) represent the significand (sometimes called the
mantissa) of the floatingpoint number.
If the argument is positive infinity, the result is 0x7ff0000000000000L
.
If the argument is negative infinity, the result is 0xfff0000000000000L
.
If the argument is NaN, the result is 0x7ff8000000000000L
.
In all cases, the result is a long
integer that, when given to the
longBitsToDouble(long)
method, will produce a floatingpoint value the same as the
argument to doubleToLongBits
(except all NaN values are collapsed to a single
"canonical" NaN value).
value
 a double
precision floatingpoint number.public static long doubleToRawLongBits(double value)
Bit 63 (the bit that is selected by the mask 0x8000000000000000L
) represents the sign
of the floatingpoint number. Bits 6252 (the bits that are selected by the mask
0x7ff0000000000000L
) represent the exponent. Bits 510 (the bits that are selected by
the mask 0x000fffffffffffffL
) represent the significand (sometimes called the
mantissa) of the floatingpoint number.
If the argument is positive infinity, the result is 0x7ff0000000000000L
.
If the argument is negative infinity, the result is 0xfff0000000000000L
.
If the argument is NaN, the result is the long
integer representing the actual NaN
value. Unlike the doubleToLongBits
method, doubleToRawLongBits
does not
collapse all the bit patterns encoding a NaN to a single "canonical" NaN value.
In all cases, the result is a long
integer that, when given to the
longBitsToDouble(long)
method, will produce a floatingpoint value the same as the
argument to doubleToRawLongBits
.
value
 a double
precision floatingpoint number.public static boolean isInfinite(double v)
true
if the specified number is infinitely large in magnitude, false
otherwise.v
 the value to be tested.true
if the value of the argument is positive infinity or negative infinity;
false
otherwise.public static boolean isNaN(double v)
true
if the specified number is a NotaNumber (NaN) value, false
otherwise.v
 the value to be tested.true
if the value of the argument is NaN; false
otherwise.public static double longBitsToDouble(long bits)
double
value corresponding to a given bit representation. The argument is
considered to be a representation of a floatingpoint value according to the IEEE 754
floatingpoint "double format" bit layout.
If the argument is 0x7ff0000000000000L
, the result is positive infinity.
If the argument is 0xfff0000000000000L
, the result is negative infinity.
If the argument is any value in the range 0x7ff0000000000001L
through
0x7fffffffffffffffL
or in the range 0xfff0000000000001L
through
0xffffffffffffffffL
, the result is a NaN. No IEEE 754 floatingpoint operation
provided by Java can distinguish between two NaN values of the same type with different bit
patterns. Distinct values of NaN are only distinguishable by use of the
Double.doubleToRawLongBits
method.
In all other cases, let s, e, and m be three values that can be computed from the argument:
Then the floatingpoint result equals the value of the mathematical expression s·m·2^{e1075}.int s = ((bits >> 63) == 0) ? 1 : 1; int e = (int) ((bits >> 52) & 0x7ffL); long m = (e == 0) ? (bits & 0xfffffffffffffL) << 1 : (bits & 0xfffffffffffffL)  0x10000000000000L;
Note that this method may not be able to return a double
NaN with exactly same bit
pattern as the long
argument. IEEE 754 distinguishes between two kinds of NaNs, quiet
NaNs and signaling NaNs. The differences between the two kinds of NaN are generally
not visible in Java. Arithmetic operations on signaling NaNs turn them into quiet NaNs with a
different, but often similar, bit pattern. However, on some processors merely copying a
signaling NaN also performs that conversion. In particular, copying a signaling NaN to return
it to the calling method may perform this conversion. So longBitsToDouble
may not be
able to return a double
with a signaling NaN bit pattern. Consequently, for some
long
values, doubleToRawLongBits(longBitsToDouble(start))
may not
equal start
. Moreover, which particular bit patterns represent signaling NaNs is
platform dependent; although all NaN bit patterns, quiet or signaling, must be in the NaN
range identified above.
bits
 any long
integer.double
floatingpoint value with the same bit pattern.public static double parseDouble(String s) throws NumberFormatException
double
initialized to the value represented by the specified
String
, as performed by the valueOf
method of class Double
.s
 the string to be parsed.double
value represented by the string argument.NullPointerException
 if the string is nullNumberFormatException
 if the string does not contain a parsable double
.valueOf(String)
public static String toString(double d)
double
argument. All characters mentioned
below are ASCII characters.
NaN
".

' (
'\u002D'
); if the sign is positive, no sign character appears in the result.
As for the magnitude m:
"Infinity"
; thus,
positive infinity produces the result "Infinity"
and negative infinity produces the
result "Infinity"
.
"0.0"
; thus, negative
zero produces the result "0.0"
and positive zero produces the result "0.0"
.
.
' ('\u002E'
), followed by one or more decimal
digits representing the fractional part of m.
.
' (
'\u002E'
), followed by decimal digits representing the fractional part of
a, followed by the letter 'E
' ('\u0045'
), followed by a
representation of n as a decimal integer, as produced by the method
Integer.toString(int)
.
double
. That is, suppose that x is the exact mathematical value
represented by the decimal representation produced by this method for a finite nonzero
argument d. Then d must be the double
value nearest to x; or if
two double
values are equally close to x, then d must be one of them
and the least significant bit of the significand of d must be 0
.d
 the double
to be converted.public static Double valueOf(double d)
Double
instance representing the specified double
value. If a new
Double
instance is not required, this method should generally be used in preference
to the constructor Double(double)
, as this method is likely to yield significantly
better space and time performance by caching frequently requested values.d
 a double value.Double
instance representing d
.public static Double valueOf(String s) throws NumberFormatException
Double
object holding the double
value represented by the argument
string s
.
If s
is null
, then a NullPointerException
is thrown.
Leading and trailing whitespace characters in s
are ignored. Whitespace is removed as
if by the String.trim()
method; that is, both ASCII space and control characters are
removed. The rest of s
should constitute a FloatValue as described by the
lexical syntax rules:
where Sign, FloatingPointLiteral, HexNumeral, HexDigits, SignedInteger and FloatTypeSuffix are as defined in the lexical structure sections of The Java™ Language Specification, except that underscores are not accepted between digits. If
 FloatValue:
 Sign_{opt}
NaN
 Sign_{opt}
Infinity
 Sign_{opt} FloatingPointLiteral
 Sign_{opt} HexFloatingPointLiteral
 SignedInteger
 HexFloatingPointLiteral:
 HexSignificand BinaryExponent FloatTypeSuffix_{opt}
 HexSignificand:
 HexNumeral
 HexNumeral
.
0x
HexDigits_{opt}.
HexDigits0X
HexDigits_{opt}.
HexDigits
 BinaryExponent:
 BinaryExponentIndicator SignedInteger
 BinaryExponentIndicator:
p
P
s
does not have the form of a FloatValue, then
a NumberFormatException
is thrown. Otherwise, s
is regarded as representing
an exact decimal value in the usual "computerized scientific notation" or as an exact
hexadecimal value; this exact numerical value is then conceptually converted to an
"infinitely precise" binary value that is then rounded to type double
by the usual
roundtonearest rule of IEEE 754 floatingpoint arithmetic, which includes preserving the
sign of a zero value.
Note that the roundtonearest rule also implies overflow and underflow behaviour; if the
exact value of s
is large enough in magnitude (greater than or equal to (
MAX_VALUE
+ ulp(MAX_VALUE)
/2), rounding to double
will result in an infinity and if the exact value of s
is small enough in magnitude
(less than or equal to MIN_VALUE
/2), rounding to float will result in a zero.
Finally, after rounding a Double
object representing this double
value is
returned.
Note that trailing format specifiers, specifiers that determine the type of a floatingpoint
literal (1.0f
is a float
value; 1.0d
is a double
value), do
not influence the results of this method. In other words, the numerical value of the
input string is converted directly to the target floatingpoint type. The twostep sequence
of conversions, string to float
followed by float
to double
, is
not equivalent to converting a string directly to double
. For example, the
float
literal 0.1f
is equal to the double
value
0.10000000149011612
; the float
literal 0.1f
represents a different
numerical value than the double
literal 0.1
. (The numerical value 0.1 cannot
be exactly represented in a binary floatingpoint number.)
s
 the string to be parsed.Double
object holding the value represented by the String
argument.NumberFormatException
 if the string does not contain a parsable number.public byte byteValue()
Double
as a byte
(by casting to a byte
).public int compareTo(Double anotherDouble)
Double
objects numerically. There are two ways in which comparisons
performed by this method differ from those performed by the Java language numerical
comparison operators (<, <=, ==, >=, >
) when applied to primitive double
values:
Double.NaN
is considered by this method to be equal to itself and greater than all
other double
values (including Double.POSITIVE_INFINITY
).
0.0d
is considered by this method to be greater than 0.0d
.
Double
objects imposed by this
method is consistent with equals.compareTo
in interface Comparable<Double>
anotherDouble
 the Double
to be compared.0
if anotherDouble
is numerically equal to this
Double
; a value less than 0
if this Double
is numerically
less than anotherDouble
; and a value greater than 0
if this
Double
is numerically greater than anotherDouble
.public double doubleValue()
double
value of this Double
object.doubleValue
in class Number
double
value represented by this objectpublic boolean equals(Object obj)
true
if and only if
the argument is not null
and is a Double
object that represents a
double
that has the same value as the double
represented by this object. For
this purpose, two double
values are considered to be the same if and only if the
method doubleToLongBits(double)
returns the identical long
value when
applied to each.
Note that in most cases, for two instances of class Double
, d1
and d2
, the value of d1.equals(d2)
is true
if and only if
d1.doubleValue() == d2.doubleValue()
also has the value true
. However, there are two exceptions:
d1
and d2
both represent Double.NaN
, then the equals
method returns true
, even though Double.NaN==Double.NaN
has the value
false
.
d1
represents +0.0
while d2
represents 0.0
, or vice
versa, the equal
test has the value false
, even though +0.0==0.0
has
the value true
.
equals
in class Object
obj
 the object to compare with.true
if the objects are the same; false
otherwise.doubleToLongBits(double)
public float floatValue()
float
value of this Double
object.floatValue
in class Number
double
value represented by this object converted to type float
public int hashCode()
Double
object. The result is the exclusive OR of the two
halves of the long
integer bit representation, exactly as produced by the method
doubleToLongBits(double)
, of the primitive double
value represented by this
Double
object. That is, the hash code is the value of the expression:
(int)(v^(v>>>32))
where v
is defined by:
long v = Double.doubleToLongBits(this.doubleValue());
hashCode
in class Object
hash code
value for this object.Object.equals(java.lang.Object)
,
System.identityHashCode(java.lang.Object)
public int intValue()
Double
as an int
(by casting to type int
).public boolean isInfinite()
true
if this Double
value is infinitely large in magnitude,
false
otherwise.true
if the value represented by this object is positive infinity or negative
infinity; false
otherwise.public boolean isNaN()
true
if this Double
value is a NotaNumber (NaN), false
otherwise.true
if the value represented by this object is NaN; false
otherwise.public long longValue()
Double
as a long
(by casting to type long
).public short shortValue()
Double
as a short
(by casting to a short
).shortValue
in class Number
double
value represented by this object converted to type short
public String toString()
Double
object. The primitive double
value represented by this object is converted to a string exactly as if by the method
toString
of one argument.toString
in class Object
String
representation of this object.toString(double)