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java.lang
Class Float
java.lang.Object
java.lang.Number
java.lang.Float

All Implemented Interfaces:

Comparable
,
Serializable

public final class
Float

extends
Number

implements
Comparable
<
Float
>
The Float class wraps a value of primitive type float in an object. An object of type Float contains a single field whose type is float.
In addition, this class provides several methods for converting a float to a String and a String to a float, as well as other constants and methods useful when dealing with a float.

Since:

JDK1.0

See Also:

Serialized Form
Field Summary

static float 
MAX_VALUE
A constant holding the largest positive finite value of type float, (22^{
23}
)·2^{
127}
. 
static float 
MIN_VALUE
A constant holding the smallest positive nonzero value of type float, 2^{
149}
. 
static float 
NaN
A constant holding a NotaNumber (NaN) value of type float. 
static float 
NEGATIVE_INFINITY
A constant holding the negative infinity of type float. 
static float 
POSITIVE_INFINITY
A constant holding the positive infinity of type float. 
static int

SIZE
The number of bits used to represent a
float
value.

static
Class

TYPE
The Class instance representing the primitive type float.

static
Class
<
Float

TYPE
The Class instance representing the primitive type float.

Constructor Summary

Float
(double value)
Constructs a newly allocated Float object that represents the argument converted to type float. 
Float
(float value)
Constructs a newly allocated Float object that represents the primitive float argument. 
Float
(
String
s)
Constructs a newly allocated Float object that represents the floatingpoint value of type float represented by the string. 
Method Summary

byte 
byteValue
()
Returns the value of this Float as a byte (by casting to a byte). 
static int 
compare
(float f1, float f2)
Compares the two specified float values. 
int 
compareTo
(
Float
anotherFloat)
Compares two Float objects numerically. 
int

compareTo
(
Object
Compares this Float object to another object.

double 
doubleValue
()
Returns the double value of this Float object. 
boolean 
equals
(
Object
obj)
Compares this object against the specified object. 
static int 
floatToIntBits
(float value)
Returns a representation of the specified floatingpoint value according to the IEEE 754 floatingpoint "single format" bit layout. 
static int 
floatToRawIntBits
(float value)
Returns a representation of the specified floatingpoint value according to the IEEE 754 floatingpoint "single format" bit layout, preserving NotaNumber (NaN) values. 
float 
floatValue
()
Returns the float value of this Float object. 
int 
hashCode
()
Returns a hash code for this Float object. 
static float 
intBitsToFloat
(int bits)
Returns the float value corresponding to a given bit represention. 
int 
intValue
()
Returns the value of this Float as an int (by casting to type int). 
boolean 
isInfinite
()
Returns true if this Float value is infinitely large in magnitude, false otherwise. 
static boolean 
isInfinite
(float v)
Returns true if the specified number is infinitely large in magnitude, false otherwise. 
boolean 
isNaN
()
Returns true if this Float value is a NotaNumber (NaN), false otherwise. 
static boolean 
isNaN
(float v)
Returns true if the specified number is a NotaNumber (NaN) value, false otherwise. 
long 
longValue
()
Returns value of this Float as a long (by casting to type long). 
static float 
parseFloat
(
String
s)
Returns a new float initialized to the value represented by the specified String, as performed by the valueOf method of class Float. 
short 
shortValue
()
Returns the value of this Float as a short (by casting to a short). 
static
String

toHexString
(float f)
Returns a hexadecimal string representation of the float argument.

String

toString
()
Returns a string representation of this Float object. 
static
String

toString
(float f)
Returns a string representation of the float argument. 
static
Float

valueOf
(float f)
Returns a
Float
instance representing the specified
float
value.

static
Float

valueOf
(
String
s)
Returns a Float object holding the float value represented by the argument string s. 
POSITIVE_INFINITY
public static final float POSITIVE_INFINITY

A constant holding the positive infinity of type float. It is equal to the value returned by Float.intBitsToFloat(0x7f800000).

See Also:

Constant Field Values
NEGATIVE_INFINITY
public static final float NEGATIVE_INFINITY

A constant holding the negative infinity of type float. It is equal to the value returned by Float.intBitsToFloat(0xff800000).

See Also:

Constant Field Values
NaN
public static final float NaN

A constant holding a NotaNumber (NaN) value of type float. It is equivalent to the value returned by Float.intBitsToFloat(0x7fc00000).

See Also:

Constant Field Values
MAX_VALUE
public static final float MAX_VALUE

A constant holding the largest positive finite value of type float, (22^{
23}
)·2^{
127}
. It is equal to the
hexadecimal floatingpoint literal 0x1.fffffeP+127f and also equal to
value returned by
Float.intBitsToFloat(0x7f7fffff).

See Also:

Constant Field Values
MIN_VALUE
public static final float MIN_VALUE

A constant holding the smallest positive nonzero value of type float, 2^{
149}
. It is equal to the
hexadecimal floatingpoint literal 0x0.000002P126f and also equal to
value returned by
Float.intBitsToFloat(0x1).

See Also:

Constant Field Values
SIZE
public static final int SIZE

The number of bits used to represent a
float
value.

Since:

1.5

See Also:

Constant Field Values
TYPE
public static final Class< Float> TYPE

The Class instance representing the primitive type float.

Since:

JDK1.1
Float
public Float(float value)

Constructs a newly allocated Float object that represents the primitive float argument.

Parameters:

value  the value to be represented by the Float.
Float
public Float(double value)

Constructs a newly allocated Float object that represents the argument converted to type float.

Parameters:

value  the value to be represented by the Float.
Float
public Float(String s)
throws NumberFormatException

Constructs a newly allocated Float object that represents the floatingpoint value of type float represented by the string. The string is converted to a float value as if by the valueOf method.

Parameters:

s  a string to be converted to a Float.

Throws:

NumberFormatException
 if the string does not contain a parsable number.

See Also:

valueOf(java.lang.String)
toString
public static String toString(float f)

Returns a string representation of the float argument. All characters mentioned below are ASCII characters.

If the argument is NaN, the result is the string "NaN".

Otherwise, the result is a string that represents the sign and magnitude (absolute value) of the argument. If the sign is negative, the first character of the result is '' ('\u002D'); if the sign is positive, no sign character appears in the result. As for the magnitude
m
:

If
m
is infinity, it is represented by the characters "Infinity"; thus, positive infinity produces the result "Infinity" and negative infinity produces the result "Infinity".

If
m
is zero, it is represented by the characters "0.0"; thus, negative zero produces the result "0.0" and positive zero produces the result "0.0".

If
m
is greater than or equal to 10^{
3}
but less than 10^{
7}
, then it is represented as the integer part of
m
, in decimal form with no leading zeroes, followed by '.' ('\u002E'), followed by one or more decimal digits representing the fractional part of
m
.

If
m
is less than 10^{
3}
or greater than or equal to 10^{
7}
, then it is represented in socalled "computerized scientific notation." Let
n
be the unique integer such that 10^{
n
}
<=
m
< 10^{
n
+1}
; then let
a
be the mathematically exact quotient of
m
and 10^{
n
}
so that 1 <=
a
< 10. The magnitude is then represented as the integer part of
a
, as a single decimal digit, followed by '.' ('\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)
.
How many digits must be printed for the fractional part of
m
or
a
? There must be at least one digit to represent the fractional part, and beyond that as many, but only as many, more digits as are needed to uniquely distinguish the argument value from adjacent values of type float. That is, suppose that
x
is the exact mathematical value represented by the decimal representation produced by this method for a finite nonzero argument
f
. Then
f
must be the float value nearest to
x
; or, if two float values are equally close to
x
, then
f
must be one of them and the least significant bit of the significand of
f
must be 0.
To create localized string representations of a floatingpoint value, use subclasses of
NumberFormat
.



Parameters:

f  the float to be converted.

Returns:

a string representation of the argument.
toHexString
public static StringtoHexString (float f)

Returns a hexadecimal string representation of the float argument. All characters mentioned below are ASCII characters.

If the argument is NaN, the result is the string "NaN".

Otherwise, the result is a string that represents the sign and magnitude (absolute value) of the argument. If the sign is negative, the first character of the result is '' ('\u002D'); if the sign is positive, no sign character appears in the result. As for the magnitude
m
:

If
m
is infinity, it is represented by the string "Infinity"; thus, positive infinity produces the result "Infinity" and negative infinity produces the result "Infinity".

If
m
is zero, it is represented by the string "0x0.0p0"; thus, negative zero produces the result "0x0.0p0" and positive zero produces the result "0x0.0p0".

If
m
is a float value with a normalized representation, substrings are used to represent the significand and exponent fields. The significand is represented by the characters "0x1." followed by a lowercase hexadecimal representation of the rest of the significand as a fraction. Trailing zeros in the hexadecimal representation are removed unless all the digits are zero, in which case a single zero is used. Next, the exponent is represented by "p" followed by a decimal string of the unbiased exponent as if produced by a call to
Integer.toString
on the exponent value.

If
m
is a float value with a subnormal representation, the significand is represented by the characters "0x0." followed by a hexadecimal representation of the rest of the significand as a fraction. Trailing zeros in the hexadecimal representation are removed. Next, the exponent is represented by "p126". Note that there must be at least one nonzero digit in a subnormal significand.
Examples
Floatingpoint Value

Hexadecimal String

1.0

0x1.0p0

1.0

0x1.0p0

2.0

0x1.0p1

3.0

0x1.8p1

0.5

0x1.0p1

0.25

0x1.0p2

Float.MAX_VALUE

0x1.fffffep127

Minimum Normal Value

0x1.0p126

Maximum Subnormal Value

0x0.fffffep126

Float.MIN_VALUE

0x0.000002p126




Parameters:

f  the float to be converted.

Returns:

a hex string representation of the argument.

Since:

1.5
valueOf
public static Float valueOf(String s)
throws NumberFormatException

Returns a Float object holding the float 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:

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
}
.
HexDigits

0X
HexDigits
_{
opt
}
.
HexDigits

BinaryExponent:

BinaryExponentIndicator SignedInteger

BinaryExponentIndicator:

p

P
where
Sign
,
and
FloatingPointLiteral
,
HexNumeral
,
HexDigits
,
SignedInteger
and
FloatTypeSuffix
are as defined in the lexical structure sections of the of the
Java Language Specification
are as defined in
§3.10.2
of the
Java Language Specification
. If 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
"computerized
scientific
notation" or as an exact hexadecimal value;
notation";
this exact
numerical
decimal
value is then conceptually converted to an
"infinitely precise"
"infinitely precise"
binary value that is then rounded to type float by the usual roundtonearest rule of IEEE 754 floatingpoint arithmetic, which includes preserving the sign of a zero value. Finally, a Float object representing this float value is returned.
To interpret localized string representations of a floatingpoint value, use subclasses of
NumberFormat
.
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. In general, the twostep sequence of conversions, string to double followed by double to float, is not equivalent to converting a string directly to float. For example, if first converted to an intermediate double and then to float, the string
"1.00000017881393421514957253748434595763683319091796875001d"
results in the float value 1.0000002f; if the string is converted directly to float, 1.000000
1
f results.
To avoid calling this method on a invalid string and having a NumberFormatException be thrown, the documentation for
Double.valueOf
lists a regular expression which can be used to screen the input.



Parameters:

s  the string to be parsed.

Returns:

a Float object holding the value represented by the String argument.

Throws:

NumberFormatException
 if the string does not contain a parsable number.
valueOf
parseFloat
public static Floatfloat valueOf parseFloat (float f) ( String s)
throws NumberFormatException

Returns a
Float
instance representing the specified
float
value. If a new
Float
instance is not required, this method should generally be used in preference to the constructor
Float(float)
, as this method is likely to to yield significantly better space and time performance by cacheing frequently requested values.
Returns a new float initialized to the value represented by the specified String, as performed by the valueOf method of class Float.



Parameters:

f  a float value.
s  the string to be parsed.

Returns:

a
Float
instance representing
f
.
the float value represented by the string argument.

Throws:

NumberFormatException
 if the string does not contain a parsable float.

Since:

1.5
1.2

See Also:

valueOf(String)
parseFloat
isNaN
public static float boolean parseFloat isNaN ( String s)
throws NumberFormatException(float v)

Returns a new float initialized to the value represented by the specified String, as performed by the valueOf method of class Float.
Returns true if the specified number is a NotaNumber (NaN) value, false otherwise.



Parameters:

s
v
 the
string
value
to be
parsed.
tested.

Returns:

the float value represented by the string argument.

Throws:

NumberFormatException
 if the string does not contain a parsable float.

Since:

1.2

See Also:

valueOf(String)
true if the argument is NaN; false otherwise.
isNaN
isInfinite
public static boolean isNaN isInfinite (float v)

Returns true if the specified number is
a NotaNumber (NaN) value,
infinitely large in magnitude,
false otherwise.



Parameters:

v  the value to be tested.

Returns:

true if the argument is
NaN;
positive infinity or negative infinity;
false otherwise.
isInfinite
isNaN
public static boolean isInfinite isNaN (float v) ()

Returns true if the specified number is infinitely large in magnitude, false otherwise.
Returns true if this Float value is a NotaNumber (NaN), false otherwise.



Parameters:

v  the value to be tested.

Returns:

true if the
argument
value represented by this object
is
positive infinity or negative infinity;
NaN;
false otherwise.
isNaN
isInfinite
public boolean isNaN isInfinite ()

Returns true if this Float value is
a NotaNumber (NaN),
infinitely large in magnitude,
false otherwise.



Returns:

true if the value represented by this object is
NaN;
positive infinity or negative infinity;
false otherwise.
isInfinite
toString
public boolean
public StringisInfinite toString ()

Returns true if this Float value is infinitely large in magnitude, false otherwise.
Returns a string representation of this Float object. The primitive float value represented by this object is converted to a String exactly as if by the method toString of one argument.


Overrides:

toString
in class
Object


Returns:

true if the value represented by this object is positive infinity or negative infinity; false otherwise.
a String representation of this object.

See Also:

toString(float)
toString
byteValue
public String
public byte toString byteValue ()

Returns a string representation of this Float object. The primitive float value represented by this object is converted to a String exactly as if by the method toString of one argument.
Returns the value of this Float as a byte (by casting to a byte).


Overrides:

toString
byteValue
in class
Object
Number


Returns:

a String representation of this object.

See Also:

toString(float)
the float value represented by this object converted to type byte
byteValue
shortValue
public byte short byteValue shortValue ()

Returns the value of this Float as a
byte
short
(by casting to a
byte).
short).


Overrides:

byteValue
shortValue
in class
Number


Returns:

the float value represented by this object converted to type
byte
short

Since:

JDK1.1
shortValue
intValue
public short int shortValue intValue ()

Returns the value of this Float as
a short
an int
(by casting to
a short).
type int).


Overrides:
Specified by:

shortValue
intValue
in class
Number


Returns:

the float value represented by this object converted to type
short

Since:

JDK1.1
int
intValue
longValue
public int long intValue longValue ()

Returns
the
value of this Float as
an int
a long
(by casting to type
int).
long).


Specified by:

intValue
longValue
in class
Number


Returns:

the float value represented by this object converted to type
int
long
longValue
floatValue
public long float longValue floatValue ()

Returns value of this Float as a long (by casting to type long).
Returns the float value of this Float object.


Specified by:

longValue
floatValue
in class
Number


Returns:

the float value represented by this object
converted to type long
floatValue
doubleValue
public float double floatValue doubleValue ()

Returns the
float
double
value of this Float object.


Specified by:

floatValue
doubleValue
in class
Number


Returns:

the float value represented by this object
is converted to type double and the result of the conversion is returned.
doubleValue
hashCode
public double int doubleValue hashCode ()

Returns the double value of this Float object.
Returns a hash code for this Float object. The result is the integer bit representation, exactly as produced by the method
floatToIntBits(float)
, of the primitive float value represented by this Float object.


Specified by:
Overrides:

doubleValue
hashCode
in class
Number
Object


Returns:

the float value represented by this object is converted to type double and the result of the conversion is returned.
a hash code value for this object.

See Also:

Object.equals(java.lang.Object)
,
Hashtable
hashCode
equals
public int boolean hashCode equals () ( Object obj)

Returns a hash code for this Float object. The result is the integer bit representation, exactly as produced by the method
floatToIntBits(float)
Compares this object against the specified object. The result is true if and only if the argument is not null and is a Float object that represents a float with the same value as the float represented by this object. For this purpose, two float values are considered to be the same if and only if the method
floatToIntBits(float)
, of the primitive float value represented by this Float object.
returns the identical int value when applied to each.
Note that in most cases, for two instances of class Float, f1 and f2, the value of f1.equals(f2) is true if and only if
f1.floatValue() == f2.floatValue()
also has the value true. However, there are two exceptions:

If f1 and f2 both represent Float.NaN, then the equals method returns true, even though Float.NaN==Float.NaN has the value false.

If f1 represents +0.0f while f2 represents 0.0f, or vice versa, the equal test has the value false, even though 0.0f==0.0f has the value true.
This definition allows hash tables to operate properly.


Overrides:

hashCode
equals
in class
Object


Parameters:

obj  the object to be compared

Returns:

a hash code value for this object.
true if the objects are the same; false otherwise.

See Also:

Object.equals(java.lang.Object)
floatToIntBits(float)
,
Hashtable
equals
floatToIntBits
public boolean
public static int equals floatToIntBits ( Object obj) (float value)

Compares this object against the specified object. The result is true if and only if the argument is not null and is a Float object that represents a float with the same value as the float represented by this object. For this purpose, two float values are considered to be the same if and only if the method
floatToIntBits(float)
returns the identical int value when applied to each.
Returns a representation of the specified floatingpoint value according to the IEEE 754 floatingpoint "single format" bit layout.
Note that in most cases, for two instances of class Float, f1 and f2, the value of f1.equals(f2) is true if and only if
f1.floatValue() == f2.floatValue()
Bit 31 (the bit that is selected by the mask 0x80000000) represents the sign of the floatingpoint number. Bits 3023 (the bits that are selected by the mask 0x7f800000) represent the exponent. Bits 220 (the bits that are selected by the mask 0x007fffff) represent the significand (sometimes called the mantissa) of the floatingpoint number.
also has the value true. However, there are two exceptions:

If f1 and f2 both represent Float.NaN, then the equals method returns true, even though Float.NaN==Float.NaN has the value false.

If f1 represents +0.0f while f2 represents 0.0f, or vice versa, the equal test has the value false, even though 0.0f==0.0f has the value true.
This definition allows hash tables to operate properly.
If the argument is positive infinity, the result is 0x7f800000.
If the argument is negative infinity, the result is 0xff800000.
If the argument is NaN, the result is 0x7fc00000.
In all cases, the result is an integer that, when given to the
intBitsToFloat(int)
method, will produce a floatingpoint value the same as the argument to floatToIntBits (except all NaN values are collapsed to a single "canonical" NaN value).


Overrides:

equals
in class
Object


Parameters:

obj  the object to be compared
value  a floatingpoint number.

Returns:

true if the objects are the same; false otherwise.

See Also:

floatToIntBits(float)
the bits that represent the floatingpoint number.
floatToIntBits
floatToRawIntBits
public static int floatToIntBits floatToRawIntBits (float value)

Returns a representation of the specified floatingpoint value according to the IEEE 754 floatingpoint "single format" bit
layout.
layout, preserving NotaNumber (NaN) values.
Bit 31 (the bit that is selected by the mask 0x80000000) represents the sign of the floatingpoint number. Bits 3023 (the bits that are selected by the mask 0x7f800000) represent the exponent. Bits 220 (the bits that are selected by the mask 0x007fffff) represent the significand (sometimes called the mantissa) of the floatingpoint number.
If the argument is positive infinity, the result is 0x7f800000.
If the argument is negative infinity, the result is 0xff800000.
If the argument is NaN, the result is 0x7fc00000.
If the argument is NaN, the result is the integer representing the actual NaN value. Unlike the floatToIntBits method, intToRawIntBits does not collapse all the bit patterns encoding a NaN to a single "canonical" NaN value.
In all cases, the result is an integer that, when given to the
intBitsToFloat(int)
method, will produce a floatingpoint value the same as the argument to
floatToIntBits (except all NaN values are collapsed to a single "canonical" NaN value).
floatToRawIntBits.



Parameters:

value  a floatingpoint number.

Returns:

the bits that represent the floatingpoint number.
floatToRawIntBits
intBitsToFloat
public static int float floatToRawIntBits intBitsToFloat (float value) (int bits)

Returns
the float value corresponding to
a
given bit represention. The argument is considered to be a
representation of
the specified
a
floatingpoint value according to the IEEE 754 floatingpoint "single format" bit
layout, preserving NotaNumber (NaN) values.
layout.
Bit 31 (the bit that is selected by the mask 0x80000000) represents the sign of the floatingpoint number. Bits 3023 (the bits that are selected by the mask 0x7f800000) represent the exponent. Bits 220 (the bits that are selected by the mask 0x007fffff) represent the significand (sometimes called the mantissa) of the floatingpoint number.
If the argument is 0x7f800000, the result is positive infinity.
If the argument is
positive infinity,
0xff800000,
the result is
0x7f800000.
negative infinity.
If the argument is negative infinity, the result is 0xff800000.
If the argument is any value in the range 0x7f800001 through 0x7fffffff or in the range 0xff800001 through 0xffffffff, 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 Float.floatToRawIntBits method.
If the argument is NaN, the result is the integer representing the actual NaN value. Unlike the floatToIntBits method, intToRawIntBits does not collapse all the bit patterns encoding a NaN to a single "canonical" NaN value.
In all other cases, let
s
,
e
, and
m
be three values that can be computed from the argument:
int s = ((bits >> 31) == 0) ? 1 : 1;
int e = ((bits >> 23) & 0xff);
int m = (e == 0) ?
(bits & 0x7fffff) << 1 :
(bits & 0x7fffff)  0x800000;
Then the floatingpoint result equals the value of the mathematical expression
s
·
m
·2
^{
e
150
}
.
In all cases, the result is an integer that, when given to the
intBitsToFloat(int)
method, will produce a floatingpoint value the same as the argument to floatToRawIntBits.
Note that this method may not be able to return a float NaN with exactly same bit pattern as the int 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 intBitsToFloat may not be able to return a float with a signaling NaN bit pattern. Consequently, for some int values, floatToRawIntBits(intBitsToFloat(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.



Parameters:

value  a floatingpoint number.
bits  an integer.

Returns:

the bits that represent the floatingpoint number.
the float floatingpoint value with the same bit pattern.
intBitsToFloat
compareTo
public static float
public int intBitsToFloat compareTo (int bits) ( Float anotherFloat)

Returns the float value corresponding to a given bit represention. The argument is considered to be a representation of a floatingpoint value according to the IEEE 754 floatingpoint "single format" bit layout.
If the argument is 0x7f800000, the result is positive infinity.
If the argument is 0xff800000, the result is negative infinity.
If the argument is any value in the range 0x7f800001 through 0x7fffffff or in the range 0xff800001 through 0xffffffff, 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 Float.floatToRawIntBits method.
In all other cases, let
Compares two Float 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 float values:

Float.NaN is considered by this method to be equal to itself and greater than all other float values (including Float.POSITIVE_INFINITY).

0.0f is considered by this method to be greater than 0.0f.
This ensures that Float.compareTo(Object) (which forwards its behavior to this method) obeys the general contract for Comparable.compareTo, and that the
s
natural order
,
on Floats is
e
consistent with equals
, and
m
be three values that can be computed from the argument:
int s = ((bits >> 31) == 0) ? 1 : 1;
int e = ((bits >> 23) & 0xff);
int m = (e == 0) ?
(bits & 0x7fffff) << 1 :
(bits & 0x7fffff)  0x800000;
Then the floatingpoint result equals the value of the mathematical expression
s
·
m
·2
^{
e
150
}
.
Note that this method may not be able to return a float NaN with exactly same bit pattern as the int 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 intBitsToFloat may not be able to return a float with a signaling NaN bit pattern. Consequently, for some int values, floatToRawIntBits(intBitsToFloat(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.



Parameters:

bits  an integer.
anotherFloat  the Float to be compared.

Returns:

the float floatingpoint value with the same bit pattern.
the value 0 if anotherFloat is numerically equal to this Float; a value less than 0 if this Float is numerically less than anotherFloat; and a value greater than 0 if this Float is numerically greater than anotherFloat.

Since:

1.2

See Also:

Comparable.compareTo(Object)
compareTo
public int compareTo( FloatObject anotherFloat) o)

Compares two Float 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 float values:

Float.NaN is considered by this method to be equal to itself and greater than all other float values (including Float.POSITIVE_INFINITY).

0.0f is considered by this method to be greater than 0.0f.
This ensures that the
natural ordering
of
Float
objects imposed by this method is
consistent with equals
.
Compares this Float object to another object. If the object is a Float, this function behaves like compareTo(Float). Otherwise, it throws a ClassCastException (as Float objects are comparable only to other Float objects).


Specified by:

compareTo
in interface
Comparable


Parameters:

anotherFloat
o
 the
Float
Object
to be compared. 
Returns:

the value 0 if anotherFloat is numerically equal to this Float; a value less than 0 if this Float is numerically less than anotherFloat; and a value greater than 0 if this Float is numerically greater than anotherFloat.
the value 0 if the argument is a Float numerically equal to this Float; a value less than 0 if the argument is a Float numerically greater than this Float; and a value greater than 0 if the argument is a Float numerically less than this Float .

Throws:

ClassCastException  if the argument is not a Float.

Since:

1.2

See Also:

Comparable.compareTo(Object)
Comparable
compare
public static int compare(float f1,
float f2)

Compares the two specified float values. The sign of the integer value returned is the same as that of the integer that would be returned by the call:
new Float(f1).compareTo(new Float(f2))



Parameters:

f1  the first float to compare.

f2  the second float to compare.

Returns:

the value 0 if f1 is numerically equal to f2; a value less than 0 if f1 is numerically less than f2; and a value greater than 0 if f1 is numerically greater than f2.

Since:

1.4