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).

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).

public static final float NaN

A constant holding a Not-a-Number (NaN) value of type float. It is equivalent to the value returned by Float.intBitsToFloat(0x7fc00000).

public static final float MAX_VALUE

A constant holding the largest positive finite value of type float, (2-2^-23)·2¹²⁷. It is equal to the hexadecimal floating-point literal 0x1.fffffeP+127f and also equal to Float.intBitsToFloat(0x7f7fffff).

public static final float MIN_NORMAL

A constant holding the smallest positive normal value of type float, 2^-126. It is equal to the hexadecimal floating-point literal 0x1.0p-126f and also equal to Float.intBitsToFloat(0x00800000).

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 floating-point literal 0x0.000002P-126f and also equal to Float.intBitsToFloat(0x1).

public static final int SIZE

The number of bits used to represent a float value.

public static final int PRECISION

The number of bits in the significand of a float value. This is the parameter N in section 4.2.3 of The Java Language Specification.

public static final int MAX_EXPONENT

Maximum exponent a finite float variable may have. It is equal to the value returned by Math.getExponent(Float.MAX_VALUE).

public static final int MIN_EXPONENT

Minimum exponent a normalized float variable may have. It is equal to the value returned by Math.getExponent(Float.MIN_NORMAL).

public static final int BYTES

The number of bytes used to represent a float value.

public static final Class<Float> TYPE

The Class instance representing the primitive type float.

@Deprecated(since="9", forRemoval=true) public Float(float value)

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

@Deprecated(since="9", forRemoval=true) public Float(double value)

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

@Deprecated(since="9", forRemoval=true) public Float(String s) throws NumberFormatException

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

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".
  • Otherwise m is positive and finite. It is converted to a string in two stages:
    • Selection of a decimal: A well-defined decimal d_m is selected to represent m. This decimal is (almost always) the shortest one that rounds to m according to the round to nearest rounding policy of IEEE 754 floating-point arithmetic.
    • Formatting as a string: The decimal d_m is formatted as a string, either in plain or in computerized scientific notation, depending on its value.

A decimal is a number of the form s×10ⁱ for some (unique) integers s > 0 and i such that s is not a multiple of 10. These integers are the significand and the exponent, respectively, of the decimal. The length of the decimal is the (unique) positive integer n meeting 10^n-1 ≤ s < 10ⁿ.

The decimal d_m for a finite positive m is defined as follows:

• Let R be the set of all decimals that round to m according to the usual round to nearest rounding policy of IEEE 754 floating-point arithmetic.
• Let p be the minimal length over all decimals in R.
• When p ≥ 2, let T be the set of all decimals in R with length p. Otherwise, let T be the set of all decimals in R with length 1 or 2.
• Define d_m as the decimal in T that is closest to m. Or if there are two such decimals in T, select the one with the even significand.

The (uniquely) selected decimal d_m is then formatted. Let s, i and n be the significand, exponent and length of d_m, respectively. Further, let e = n + i - 1 and let s₁…s_n be the usual decimal expansion of s. Note that s₁ ≠ 0 and s_n ≠ 0. Below, the decimal point '.' is '\u002E' and the exponent indicator 'E' is '\u0045'.

• Case -3 ≤ e < 0: d_m is formatted as 0.0…0s₁…s_n, where there are exactly -(n + i) zeroes between the decimal point and s₁. For example, 123 × 10^-4 is formatted as 0.0123.
• Case 0 ≤ e < 7:
  • Subcase i ≥ 0: d_m is formatted as s₁…s_n0…0.0, where there are exactly i zeroes between s_n and the decimal point. For example, 123 × 10² is formatted as 12300.0.
  • Subcase i < 0: d_m is formatted as s₁…s_n+i.s_n+i+1…s_n, where there are exactly -i digits to the right of the decimal point. For example, 123 × 10^-1 is formatted as 12.3.
• Case e < -3 or e ≥ 7: computerized scientific notation is used to format d_m. Here e is formatted as by Integer.toString(int).
  • Subcase n = 1: d_m is formatted as s₁.0Ee. For example, 1 × 10²³ is formatted as 1.0E23.
  • Subcase n > 1: d_m is formatted as s₁.s₂…s_nEe. For example, 123 × 10^-21 is formatted as 1.23E-19.

To create localized string representations of a floating-point value, use subclasses of NumberFormat.

public static String toHexString(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 "p-126". Note that there must be at least one nonzero digit in a subnormal significand.

Examples

Floating-point Value	Hexadecimal String
1.0	0x1.0p0
-1.0	-0x1.0p0
2.0	0x1.0p1
3.0	0x1.8p1
0.5	0x1.0p-1
0.25	0x1.0p-2
Float.MAX_VALUE	0x1.fffffep127
Minimum Normal Value	0x1.0p-126
Maximum Subnormal Value	0x0.fffffep-126
Float.MIN_VALUE	0x0.000002p-126

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, 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 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 float by the usual round-to-nearest rule of IEEE 754 floating-point arithmetic, which includes preserving the sign of a zero value. Note that the round-to-nearest 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 float 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 Float object representing this float value is returned.

To interpret localized string representations of a floating-point value, use subclasses of NumberFormat.

Note that trailing format specifiers, specifiers that determine the type of a floating-point 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 floating-point type. In general, the two-step 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, 1.0000001f results.

To avoid calling this method on an 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.

public static Float valueOf(float f)

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 yield significantly better space and time performance by caching frequently requested values.

public static float parseFloat(String s) throws NumberFormatException

Returns a new float initialized to the value represented by the specified String, as performed by the valueOf method of class Float.

public static boolean isNaN(float v)

Returns true if the specified number is a Not-a-Number (NaN) value, false otherwise.

public static boolean isInfinite(float v)

Returns true if the specified number is infinitely large in magnitude, false otherwise.

public static boolean isFinite(float f)

Returns true if the argument is a finite floating-point value; returns false otherwise (for NaN and infinity arguments).

public boolean isNaN()

Returns true if this Float value is a Not-a-Number (NaN), false otherwise.

public boolean isInfinite()

Returns true if this Float value is infinitely large in magnitude, false otherwise.

public String toString()

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.

public byte byteValue()

Returns the value of this Float as a byte after a narrowing primitive conversion.

public short shortValue()

Returns the value of this Float as a short after a narrowing primitive conversion.

public int intValue()

Returns the value of this Float as an int after a narrowing primitive conversion.

public long longValue()

Returns value of this Float as a long after a narrowing primitive conversion.

public float floatValue()

Returns the float value of this Float object.

public double doubleValue()

Returns the value of this Float as a double after a widening primitive conversion.

public int hashCode()

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.

public static int hashCode(float value)

Returns a hash code for a float value; compatible with Float.hashCode().

public boolean equals(Object obj)

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.

public static int floatToIntBits(float value)

Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "single format" bit layout.

Bit 31 (the bit that is selected by the mask 0x80000000) represents the sign of the floating-point number. Bits 30-23 (the bits that are selected by the mask 0x7f800000) represent the exponent. Bits 22-0 (the bits that are selected by the mask 0x007fffff) represent the significand (sometimes called the mantissa) of the floating-point 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.

In all cases, the result is an integer that, when given to the intBitsToFloat(int) method, will produce a floating-point value the same as the argument to floatToIntBits (except all NaN values are collapsed to a single "canonical" NaN value).

public static int floatToRawIntBits(float value)

Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "single format" bit layout, preserving Not-a-Number (NaN) values.

Bit 31 (the bit that is selected by the mask 0x80000000) represents the sign of the floating-point number. Bits 30-23 (the bits that are selected by the mask 0x7f800000) represent the exponent. Bits 22-0 (the bits that are selected by the mask 0x007fffff) represent the significand (sometimes called the mantissa) of the floating-point 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 the integer representing the actual NaN value. Unlike the floatToIntBits method, floatToRawIntBits 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 floating-point value the same as the argument to floatToRawIntBits.

public static float intBitsToFloat(int bits)

Returns the float value corresponding to a given bit representation. The argument is considered to be a representation of a floating-point value according to the IEEE 754 floating-point "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 floating-point 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 s, e, and m be three values that can be computed from the argument:

Then the floating-point 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.

public static float float16ToFloat(short floatBinary16)

Returns the float value closest to the numerical value of the argument, a floating-point binary16 value encoded in a short. The conversion is exact; all binary16 values can be exactly represented in float. Special cases:

• If the argument is zero, the result is a zero with the same sign as the argument.
• If the argument is infinite, the result is an infinity with the same sign as the argument.
• If the argument is a NaN, the result is a NaN.

IEEE 754 binary16 format

The IEEE 754 standard defines binary16 as a 16-bit format, along with the 32-bit binary32 format (corresponding to the float type) and the 64-bit binary64 format (corresponding to the double type). The binary16 format is similar to the other IEEE 754 formats, except smaller, having all the usual IEEE 754 values such as NaN, signed infinities, signed zeros, and subnormals. The parameters (JLS 4.2.3) for the binary16 format are N = 11 precision bits, K = 5 exponent bits, E_max = 15, and E_min = -14.

public static short floatToFloat16(float f)

Returns the floating-point binary16 value, encoded in a short, closest in value to the argument. The conversion is computed under the round to nearest even rounding mode. Special cases:

• If the argument is zero, the result is a zero with the same sign as the argument.
• If the argument is infinite, the result is an infinity with the same sign as the argument.
• If the argument is a NaN, the result is a NaN.

The binary16 format is discussed in more detail in the float16ToFloat(short) method.

public int compareTo(Float anotherFloat)

Compares two Float objects numerically. This method imposes a total order on Float objects with two differences compared to the incomplete order defined by the Java language numerical comparison operators (<, <=, ==, >=, >) on float values.

• A NaN is unordered with respect to other values and unequal to itself under the comparison operators. This method chooses to define Float.NaN to be equal to itself and greater than all other double values (including Float.POSITIVE_INFINITY).
• Positive zero and negative zero compare equal numerically, but are distinct and distinguishable values. This method chooses to define positive zero (+0.0f), to be greater than negative zero (-0.0f).

This ensures that the natural ordering of Float objects imposed by this method is consistent with equals; see this discussion for details of floating-point comparison and ordering.

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:

    Float.valueOf(f1).compareTo(Float.valueOf(f2))
 

public static float sum(float a, float b)

Adds two float values together as per the + operator.

public static float max(float a, float b)

Returns the greater of two float values as if by calling Math.max.

public static float min(float a, float b)

Returns the smaller of two float values as if by calling Math.min.

public Optional<Float> describeConstable()

Returns an Optional containing the nominal descriptor for this instance, which is the instance itself.

public Float resolveConstantDesc(MethodHandles.Lookup lookup)

Resolves this instance as a ConstantDesc, the result of which is the instance itself.