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`java.lang.Object`

`java.lang.Number`

`java.lang.Double`

**Implemented Interfaces:**- Comparable<T>, Serializable

Instances of class

`Double`

represent primitive
`double`

values.
Additionally, this class provides various helper functions and variables
related to doubles.
**Since:**- 1.0

**See Also:**- Serialized Form

## Field Summary

`static double`

`MAX_VALUE`

- The maximum positive value a
`double`

may represent is 1.7976931348623157e+308.

`static double`

`MIN_VALUE`

- The minimum positive value a
`double`

may represent is 5e-324.

`static double`

`NEGATIVE_INFINITY`

- The value of a double representation -1.0/0.0, negative infinity.

`static double`

`NaN`

- All IEEE 754 values of NaN have the same value in Java.

`static double`

`POSITIVE_INFINITY`

- The value of a double representing 1.0/0.0, positive infinity.

`static int`

`SIZE`

- The number of bits needed to represent a
`double`

.

`static Class`

`TYPE`

- The primitive type
`double`

is represented by this`Class`

object.

## Constructor Summary

`Double(double value)`

- Create a
`Double`

from the primitive`double`

specified.

## Method Summary

`byte`

`byteValue()`

- Return the value of this
`Double`

as a`byte`

.

`static int`

`compare(double x, double y)`

- Behaves like
`new Double(x).compareTo(new Double(y))`

; in other words this compares two doubles, special casing NaN and zero, without the overhead of objects.

`int`

`static long`

`doubleToLongBits(double value)`

- Convert the double to the IEEE 754 floating-point "double format" bit layout.

`static long`

`doubleToRawLongBits(double value)`

- Convert the double to the IEEE 754 floating-point "double format" bit layout.

`double`

`doubleValue()`

- Return the value of this
`Double`

.

`boolean`

`float`

`floatValue()`

- Return the value of this
`Double`

as a`float`

.

`int`

`hashCode()`

- Return a hashcode representing this Object.

`int`

`intValue()`

- Return the value of this
`Double`

as an`int`

.

`boolean`

`isInfinite()`

- Return
`true`

if the value of this`Double`

is the same as`NEGATIVE_INFINITY`

or`POSITIVE_INFINITY`

, otherwise return`false`

.

`static boolean`

`isInfinite(double v)`

- Return
`true`

if the`double`

has a value equal to either`NEGATIVE_INFINITY`

or`POSITIVE_INFINITY`

, otherwise return`false`

.

`boolean`

`isNaN()`

- Return
`true`

if the value of this`Double`

is the same as`NaN`

, otherwise return`false`

.

`static boolean`

`isNaN(double v)`

- Return
`true`

if the`double`

has the same value as`NaN`

, otherwise return`false`

.

`static double`

`longBitsToDouble(long bits)`

- Convert the argument in IEEE 754 floating-point "double format" bit layout to the corresponding float.

`long`

`longValue()`

- Return the value of this
`Double`

as a`long`

.

`static double`

`parseDouble(String str)`

- Parse the specified
`String`

as a`double`

.

`short`

`shortValue()`

- Return the value of this
`Double`

as a`short`

.

`static String`

`toHexString(double d)`

- Convert a double value to a hexadecimal string.

`String`

`toString()`

- Convert the
`double`

value of this`Double`

to a`String`

.

`static String`

`toString(double d)`

- Convert the
`double`

to a`String`

.

`static Double`

`valueOf(double val)`

- Returns a
`Double`

object wrapping the value.

`static Double`

### Methods inherited from class java.lang.Number

`byteValue`

,`doubleValue`

,`floatValue`

,`intValue`

,`longValue`

,`shortValue`

### Methods inherited from class java.lang.Object

`clone`

,`equals`

,`extends Object> getClass`

,`finalize`

,`hashCode`

,`notify`

,`notifyAll`

,`toString`

,`wait`

,`wait`

,`wait`

public static final double MAX_VALUE

The maximum positive value a`double`

may represent is 1.7976931348623157e+308.

Field Value:- 2.147483648E9

public static final double MIN_VALUE

The minimum positive value a`double`

may represent is 5e-324.

Field Value:- 0.0

public static final double NEGATIVE_INFINITY

The value of a double representation -1.0/0.0, negative infinity.

Field Value:- -2.147483648E9

public static final double NaN

All IEEE 754 values of NaN have the same value in Java.

Field Value:- 0.0

public static final double POSITIVE_INFINITY

The value of a double representing 1.0/0.0, positive infinity.

Field Value:- 2.147483648E9

public static final int SIZE

The number of bits needed to represent a`double`

.

Field Value:- 64

Since:- 1.5

public static final ClassTYPE

The primitive type`double`

is represented by this`Class`

object.

Since:- 1.1

public Double(double value)

Create a`Double`

from the primitive`double`

specified.

Parameters:`value`

- the`double`

argument

public Double(String s)

Create a`Double`

from the specified`String`

. This method calls`Double.parseDouble()`

.

Parameters:`s`

- the`String`

to convert

Throws:`NumberFormatException`

- if`s`

cannot be parsed as a`double`

`NullPointerException`

- if`s`

is null

See Also:`parseDouble(String)`

public byte byteValue()

Return the value of this`Double`

as a`byte`

.

Returns:- the byte value

Since:- 1.1

public static int compare(double x, double y)

Behaves like`new Double(x).compareTo(new Double(y))`

; in other words this compares two doubles, special casing NaN and zero, without the overhead of objects.

Parameters:`x`

- the first double to compare`y`

- the second double to compare

Returns:- the comparison

Since:- 1.4

public int compareTo(Double d)

Compare two Doubles numerically by comparing their`double`

values. The result is positive if the first is greater, negative if the second is greater, and 0 if the two are equal. However, this special cases NaN and signed zero as follows: NaN is considered greater than all other doubles, including`POSITIVE_INFINITY`

, and positive zero is considered greater than negative zero.

Parameters:`d`

- the Double to compare

Returns:- the comparison

Since:- 1.2

public static long doubleToLongBits(double value)

Convert the double to the IEEE 754 floating-point "double format" bit layout. Bit 63 (the most significant) is the sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa. This function collapses all versions of NaN to 0x7ff8000000000000L. The result of this function can be used as the argument to`Double.longBitsToDouble(long)`

to obtain the original`double`

value.

Parameters:`value`

- the`double`

to convert

Returns:- the bits of the
`double`

See Also:`longBitsToDouble(long)`

public static long doubleToRawLongBits(double value)

Convert the double to the IEEE 754 floating-point "double format" bit layout. Bit 63 (the most significant) is the sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa. This function leaves NaN alone, rather than collapsing to a canonical value. The result of this function can be used as the argument to`Double.longBitsToDouble(long)`

to obtain the original`double`

value.

Parameters:`value`

- the`double`

to convert

Returns:- the bits of the
`double`

See Also:`longBitsToDouble(long)`

public double doubleValue()

Return the value of this`Double`

.

Overrides:- doubleValue in interface Number

Returns:- the double value

public boolean equals(Object obj)

Returns`true`

if`obj`

is an instance of`Double`

and represents the same double value. Unlike comparing two doubles with`==`

, this treats two instances of`Double.NaN`

as equal, but treats`0.0`

and`-0.0`

as unequal.Note that

`d1.equals(d2)`

is identical to`doubleToLongBits(d1.doubleValue()) == doubleToLongBits(d2.doubleValue())`

.

Parameters:`obj`

- the object to compare

Returns:- whether the objects are semantically equal

public float floatValue()

Return the value of this`Double`

as a`float`

.

Overrides:- floatValue in interface Number

Returns:- the float value

public int hashCode()

Return a hashcode representing this Object.`Double`

's hash code is calculated by:

`long v = Double.doubleToLongBits(doubleValue());`

.

int hash = (int)(v^(v>>32))

Returns:- this Object's hash code

See Also:`doubleToLongBits(double)`

public boolean isInfinite()

Return`true`

if the value of this`Double`

is the same as`NEGATIVE_INFINITY`

or`POSITIVE_INFINITY`

, otherwise return`false`

.

Returns:- whether this
`Double`

is (-/+) infinity

public static boolean isInfinite(double v)

Return`true`

if the`double`

has a value equal to either`NEGATIVE_INFINITY`

or`POSITIVE_INFINITY`

, otherwise return`false`

.

Parameters:`v`

- the`double`

to compare

Returns:- whether the argument is (-/+) infinity.

public boolean isNaN()

Return`true`

if the value of this`Double`

is the same as`NaN`

, otherwise return`false`

.

Returns:- whether this
`Double`

is`NaN`

public static boolean isNaN(double v)

Return`true`

if the`double`

has the same value as`NaN`

, otherwise return`false`

.

Parameters:`v`

- the`double`

to compare

Returns:- whether the argument is
`NaN`

.

public static double longBitsToDouble(long bits)

Convert the argument in IEEE 754 floating-point "double format" bit layout to the corresponding float. Bit 63 (the most significant) is the sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa. This function leaves NaN alone, so that you can recover the bit pattern with`Double.doubleToRawLongBits(double)`

.

Parameters:`bits`

- the bits to convert

Returns:- the
`double`

represented by the bits

public static double parseDouble(String str)

Parse the specified`String`

as a`double`

. The extended BNF grammar is as follows:

DecodableString: ( [`-`

|`+`

]`NaN`

) | ( [`-`

|`+`

]`Infinity`

) | ( [`-`

|`+`

]FloatingPoint[`f`

|`F`

|`d`

|`D`

] )FloatingPoint: ( {Digit}+ [`.`

{Digit} ] [Exponent] ) | (`.`

{Digit}+ [Exponent] )Exponent: ( (`e`

|`E`

) [`-`

|`+`

] {Digit}+ )Digit:`'0'`

through`'9'`

NaN and infinity are special cases, to allow parsing of the output of toString. Otherwise, the result is determined by calculating

n * 10to infinite precision, then rounding to the nearest double. Remember that many numbers cannot be precisely represented in floating point. In case of overflow, infinity is used, and in case of underflow, signed zero is used. Unlike Integer.parseInt, this does not accept Unicode digits outside the ASCII range.^{exponent}If an unexpected character is found in the

`String`

, a`NumberFormatException`

will be thrown. Leading and trailing 'whitespace' is ignored via`String.trim()`

, but spaces internal to the actual number are not allowed.To parse numbers according to another format, consider using

`NumberFormat`

.

Parameters:`str`

- the`String`

to convert

Returns:- the
`double`

value of`s`

Throws:`NumberFormatException`

- if`s`

cannot be parsed as a`double`

`NullPointerException`

- if`s`

is null

Since:- 1.2

See Also:`MIN_VALUE`

,`MAX_VALUE`

,`POSITIVE_INFINITY`

,`NEGATIVE_INFINITY`

public short shortValue()

Return the value of this`Double`

as a`short`

.

Overrides:- shortValue in interface Number

Returns:- the short value

Since:- 1.1

public static String toHexString(double d)

Convert a double value to a hexadecimal string. This converts as follows:

- A NaN value is converted to the string "NaN".
- Positive infinity is converted to the string "Infinity".
- Negative infinity is converted to the string "-Infinity".
- For all other values, the first character of the result is '-' if the value is negative. This is followed by '0x1.' if the value is normal, and '0x0.' if the value is denormal. This is then followed by a (lower-case) hexadecimal representation of the mantissa, with leading zeros as required for denormal values. The next character is a 'p', and this is followed by a decimal representation of the unbiased exponent.

Parameters:`d`

- the double value

Returns:- the hexadecimal string representation

Since:- 1.5

public String toString()

Convert the`double`

value of this`Double`

to a`String`

. This method calls`Double.toString(double)`

to do its dirty work.

Returns:- the
`String`

representation

See Also:`toString(double)`

public static String toString(double d)

Convert the`double`

to a`String`

. Floating-point string representation is fairly complex: here is a rundown of the possible values. "`[-]`

" indicates that a negative sign will be printed if the value (or exponent) is negative. "`<number>`

" means a string of digits ('0' to '9'). "`<digit>`

" means a single digit ('0' to '9').

Yes, negative zero

Value of Double String Representation [+-] 0 `[-]0.0`

Between [+-] 10 ^{-3}and 10^{7}, exclusive`[-]number.number`

Other numeric value `[-]<digit>.<number> E[-]<number>`

[+-] infinity `[-]Infinity`

NaN `NaN`

isa possible value. Note that there isalwaysa`.`

and at least one digit printed after it: even if the number is 3, it will be printed as`3.0`

. After the ".", all digits will be printed except trailing zeros. The result is rounded to the shortest decimal number which will parse back to the same double.To create other output formats, use

`NumberFormat`

.

Parameters:`d`

- the`double`

to convert

Returns:- the
`String`

representing the`double`

public static Double valueOf(double val)

Returns a`Double`

object wrapping the value. In contrast to the`Double`

constructor, this method may cache some values. It is used by boxing conversion.

Parameters:`val`

- the value to wrap

Returns:- the
`Double`

Since:- 1.5

public static Double valueOf(String s)

Create a new`Double`

object using the`String`

.

Parameters:`s`

- the`String`

to convert

Returns:- the new
`Double`

Throws:`NumberFormatException`

- if`s`

cannot be parsed as a`double`

`NullPointerException`

- if`s`

is null.

See Also:`parseDouble(String)`

Double.java -- object wrapper for double
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Free Software Foundation, Inc.
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