Class Float

java.lang.Object
java.lang.Number
java.lang.Float
All Implemented Interfaces:
Serializable,Comparable<Float>,Constable,ConstantDesc

public final classFloatextendsNumberimplementsComparable<Float>,Constable,ConstantDesc
TheFloat class is thewrapper class for values of the primitive typefloat. An object of typeFloat contains a single field whose type isfloat.

In addition, this class provides several methods for converting afloat to aString and aString to afloat, as well as other constants and methods useful when dealing with afloat.

This is avalue-based class; programmers should treat instances that areequal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail.

Floating-point Equality, Equivalence, and Comparison

The classjava.lang.Double has adiscussion of equality, equivalence, and comparison of floating-point values that is equally applicable tofloat values.

Decimal ↔ Binary Conversion Issues

Thediscussion of binary to decimal conversion issues injava.lang.Double is also applicable tofloat values.
Since:
1.0
External Specifications
See Also:
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    The number of bytes used to represent afloat value, 4.
    static final int
    Maximum exponent a finitefloat variable may have, 127.
    static final float
    A constant holding the largest positive finite value of typefloat, (2-2-23)·2127.
    static final int
    Minimum exponent a normalizedfloat variable may have, -126.
    static final float
    A constant holding the smallest positive normal value of typefloat, 2-126.
    static final float
    A constant holding the smallest positive nonzero value of typefloat, 2-149.
    static final float
    A constant holding a Not-a-Number (NaN) value of typefloat.
    static final float
    A constant holding the negative infinity of typefloat.
    static final float
    A constant holding the positive infinity of typefloat.
    static final int
    The number of bits in the significand of afloat value, 24.
    static final int
    The number of bits used to represent afloat value, 32.
    static finalClass<Float>
    TheClass instance representing the primitive typefloat.
  • Constructor Summary

    Constructors
    Constructor
    Description
    Float(double value)
    Deprecated, for removal: This API element is subject to removal in a future version.
    It is rarely appropriate to use this constructor.
    Float(float value)
    Deprecated, for removal: This API element is subject to removal in a future version.
    It is rarely appropriate to use this constructor.
    Deprecated, for removal: This API element is subject to removal in a future version.
    It is rarely appropriate to use this constructor.
  • Method Summary

    Modifier and Type
    Method
    Description
    byte
    Returns the value of thisFloat as abyte after a narrowing primitive conversion.
    static int
    compare(float f1, float f2)
    Compares the two specifiedfloat values.
    int
    compareTo(Float anotherFloat)
    Compares twoFloat objects numerically.
    Returns anOptional containing the nominal descriptor for this instance, which is the instance itself.
    double
    Returns the value of thisFloat as adouble after a widening primitive conversion.
    boolean
    Compares this object against the specified object.
    static float
    float16ToFloat(short floatBinary16)
    Returns thefloat value closest to the numerical value of the argument, a floating-point binary16 value encoded in ashort.
    static short
    floatToFloat16(float f)
    Returns the floating-point binary16 value, encoded in a short, closest in value to the argument.
    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.
    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.
    float
    Returns thefloat value of thisFloat object.
    int
    Returns a hash code for thisFloat object.
    static int
    hashCode(float value)
    Returns a hash code for afloat value; compatible withFloat.hashCode().
    static float
    intBitsToFloat(int bits)
    Returns thefloat value corresponding to a given bit representation.
    int
    Returns the value of thisFloat as anint after a narrowing primitive conversion.
    static boolean
    isFinite(float f)
    Returnstrue if the argument is a finite floating-point value; returnsfalse otherwise (for NaN and infinity arguments).
    boolean
    Returnstrue if thisFloat value is infinitely large in magnitude,false otherwise.
    static boolean
    isInfinite(float v)
    Returnstrue if the specified number is infinitely large in magnitude,false otherwise.
    boolean
    Returnstrue if thisFloat value is a Not-a-Number (NaN),false otherwise.
    static boolean
    isNaN(float v)
    Returnstrue if the specified number is a Not-a-Number (NaN) value,false otherwise.
    long
    Returns value of thisFloat as along after a narrowing primitive conversion.
    static float
    max(float a, float b)
    Returns the greater of twofloat values as if by callingMath.max.
    static float
    min(float a, float b)
    Returns the smaller of twofloat values as if by callingMath.min.
    static float
    Returns a newfloat initialized to the value represented by the specifiedString, as performed by thevalueOf method of classFloat.
    Resolves this instance as aConstantDesc, the result of which is the instance itself.
    short
    Returns the value of thisFloat as ashort after a narrowing primitive conversion.
    static float
    sum(float a, float b)
    Adds twofloat values together as per the + operator.
    staticString
    toHexString(float f)
    Returns a hexadecimal string representation of thefloat argument.
    Returns a string representation of thisFloat object.
    staticString
    toString(float f)
    Returns a string representation of thefloat argument.
    staticFloat
    valueOf(float f)
    Returns aFloat instance representing the specifiedfloat value.
    staticFloat
    Returns aFloat object holding thefloat value represented by the argument strings.

    Methods declared in class java.lang.Object

    clone,finalize,getClass,notify,notifyAll,wait,wait,wait
  • Field Details

    • POSITIVE_INFINITY

      public static final float POSITIVE_INFINITY
      A constant holding the positive infinity of typefloat. It is equal to the value returned byFloat.intBitsToFloat(0x7f800000).
      See Also:
    • NEGATIVE_INFINITY

      public static final float NEGATIVE_INFINITY
      A constant holding the negative infinity of typefloat. It is equal to the value returned byFloat.intBitsToFloat(0xff800000).
      See Also:
    • NaN

      public static final float NaN
      A constant holding a Not-a-Number (NaN) value of typefloat. It isequivalent to the value returned byFloat.intBitsToFloat(0x7fc00000).
      See Also:
    • MAX_VALUE

      public static final float MAX_VALUE
      A constant holding the largest positive finite value of typefloat, (2-2-23)·2127. It is equal to the hexadecimal floating-point literal0x1.fffffeP+127f and also equal toFloat.intBitsToFloat(0x7f7fffff).
      See Also:
    • MIN_NORMAL

      public static final float MIN_NORMAL
      A constant holding the smallest positive normal value of typefloat, 2-126. It is equal to the hexadecimal floating-point literal0x1.0p-126f and also equal toFloat.intBitsToFloat(0x00800000).
      Since:
      1.6
      See Also:
    • MIN_VALUE

      public static final float MIN_VALUE
      A constant holding the smallest positive nonzero value of typefloat, 2-149. It is equal to the hexadecimal floating-point literal0x0.000002P-126f and also equal toFloat.intBitsToFloat(0x1).
      See Also:
    • SIZE

      public static final int SIZE
      The number of bits used to represent afloat value, 32.
      Since:
      1.5
      See Also:
    • PRECISION

      public static final int PRECISION
      The number of bits in the significand of afloat value, 24. This is the parameter N in section4.2.3 ofThe Java Language Specification.
      Since:
      19
      See Also:
    • MAX_EXPONENT

      public static final int MAX_EXPONENT
      Maximum exponent a finitefloat variable may have, 127. It is equal to the value returned by Math.getExponent(Float.MAX_VALUE).
      Since:
      1.6
      See Also:
    • MIN_EXPONENT

      public static final int MIN_EXPONENT
      Minimum exponent a normalizedfloat variable may have, -126. It is equal to the value returned by Math.getExponent(Float.MIN_NORMAL).
      Since:
      1.6
      See Also:
    • BYTES

      public static final int BYTES
      The number of bytes used to represent afloat value, 4.
      Since:
      1.8
      See Also:
    • TYPE

      public static final Class<Float> TYPE
      TheClass instance representing the primitive typefloat.
      Since:
      1.1
  • Constructor Details

    • Float

      @Deprecated(since="9",forRemoval=true)public Float(float value)
      Deprecated, for removal: This API element is subject to removal in a future version.
      It is rarely appropriate to use this constructor. The static factoryvalueOf(float) is generally a better choice, as it is likely to yield significantly better space and time performance.
      Constructs a newly allocatedFloat object that represents the primitivefloat argument.
      Parameters:
      value - the value to be represented by theFloat.
    • Float

      @Deprecated(since="9",forRemoval=true)public Float(double value)
      Deprecated, for removal: This API element is subject to removal in a future version.
      It is rarely appropriate to use this constructor. Instead, use the static factory methodvalueOf(float) method as follows:Float.valueOf((float)value).
      Constructs a newly allocatedFloat object that represents the argument converted to typefloat.
      Parameters:
      value - the value to be represented by theFloat.
    • Float

      @Deprecated(since="9",forRemoval=true)public Float(String s) throwsNumberFormatException
      Deprecated, for removal: This API element is subject to removal in a future version.
      It is rarely appropriate to use this constructor. UseparseFloat(String) to convert a string to afloat primitive, or usevalueOf(String) to convert a string to aFloat object.
      Constructs a newly allocatedFloat object that represents the floating-point value of typefloat represented by the string. The string is converted to afloat value as if by thevalueOf method.
      Parameters:
      s - a string to be converted to aFloat.
      Throws:
      NumberFormatException - if the string does not contain a parsable number.
  • Method Details

    • toString

      public static String toString(float f)
      Returns a string representation of thefloat 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 magnitudem:
        • Ifm is infinity, it is represented by the characters"Infinity"; thus, positive infinity produces the result"Infinity" and negative infinity produces the result"-Infinity".
        • Ifm 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".
        • Otherwisem is positive and finite. It is converted to a string in two stages:
          • Selection of a decimal: A well-defined decimaldm is selected to representm. This decimal is (almost always) theshortest one that rounds tom according to the round to nearest rounding policy of IEEE 754 floating-point arithmetic.
          • Formatting as a string: The decimaldm is formatted as a string, either in plain or in computerized scientific notation, depending on its value.

      Adecimal is a number of the forms×10i for some (unique) integerss > 0 andi such thats is not a multiple of 10. These integers are thesignificand and theexponent, respectively, of the decimal. Thelength of the decimal is the (unique) positive integern meeting 10n-1s < 10n.

      The decimaldm for a finite positivem is defined as follows:

      • LetR be the set of all decimals that round tom according to the usualround to nearest rounding policy of IEEE 754 floating-point arithmetic.
      • Letp be the minimal length over all decimals inR.
      • Whenp ≥ 2, letT be the set of all decimals inR with lengthp. Otherwise, letT be the set of all decimals inR with length 1 or 2.
      • Definedm as the decimal inT that is closest tom. Or if there are two such decimals inT, select the one with the even significand.

      The (uniquely) selected decimaldm is then formatted. Lets,i andn be the significand, exponent and length ofdm, respectively. Further, lete =n +i - 1 and lets1sn be the usual decimal expansion ofs. Note thats1 ≠ 0 andsn ≠ 0. Below, the decimal point'.' is'\u002E' and the exponent indicator'E' is'\u0045'.

      • Case -3 ≤e < 0:dm is formatted as0.00s1sn, where there are exactly -(n +i) zeroes between the decimal point ands1. For example, 123 × 10-4 is formatted as0.0123.
      • Case 0 ≤e < 7:
        • Subcasei ≥ 0:dm is formatted ass1sn00.0, where there are exactlyi zeroes betweensn and the decimal point. For example, 123 × 102 is formatted as12300.0.
        • Subcasei < 0:dm is formatted ass1sn+i.sn+i+1sn, where there are exactly -i digits to the right of the decimal point. For example, 123 × 10-1 is formatted as12.3.
      • Casee < -3 ore ≥ 7: computerized scientific notation is used to formatdm. Heree is formatted as byInteger.toString(int).
        • Subcasen = 1:dm is formatted ass1.0Ee. For example, 1 × 1023 is formatted as1.0E23.
        • Subcasen > 1:dm is formatted ass1.s2snEe. For example, 123 × 10-21 is formatted as1.23E-19.

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

      API Note:
      This method corresponds to the general functionality of the convertToDecimalCharacter operation defined in IEEE 754; however, that operation is defined in terms of specifying the number of significand digits used in the conversion. Code to do such a conversion in the Java platform includes converting thefloat to aBigDecimal exactly and then rounding theBigDecimal to the desired number of digits; sample code:
      floatf = 0.1f;int digits = 15;BigDecimal bd = new BigDecimal(f);String result = bd.round(new MathContext(digits,  RoundingMode.HALF_UP));// 0.100000001490116
      Parameters:
      f - thefloat to be converted.
      Returns:
      a string representation of the argument.
    • toHexString

      public static String toHexString(float f)
      Returns a hexadecimal string representation of thefloat 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 magnitudem:
        • Ifm is infinity, it is represented by the string"Infinity"; thus, positive infinity produces the result"Infinity" and negative infinity produces the result"-Infinity".
        • Ifm 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".
        • Ifm is afloat 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 toInteger.toString on the exponent value.
        • Ifm is afloat 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 ValueHexadecimal String
      1.00x1.0p0
      -1.0-0x1.0p0
      2.00x1.0p1
      3.00x1.8p1
      0.50x1.0p-1
      0.250x1.0p-2
      Float.MAX_VALUE0x1.fffffep127
      Minimum Normal Value0x1.0p-126
      Maximum Subnormal Value0x0.fffffep-126
      Float.MIN_VALUE0x0.000002p-126
      API Note:
      This method corresponds to the convertToHexCharacter operation defined in IEEE 754.
      Parameters:
      f - thefloat to be converted.
      Returns:
      a hex string representation of the argument.
      Since:
      1.5
    • valueOf

      public static Float valueOf(String s) throwsNumberFormatException
      Returns aFloat object holding thefloat value represented by the argument strings.

      Ifs isnull, then aNullPointerException is thrown.

      Leading and trailing whitespace characters ins are ignored. Whitespace is removed as if by theString.trim() method; that is, both ASCII space and control characters are removed. The rest ofs should constitute aFloatValue as described by the lexical syntax rules:

      FloatValue:
      SignoptNaN
      SignoptInfinity
      Signopt FloatingPointLiteral
      Signopt HexFloatingPointLiteral
      SignedInteger
      HexFloatingPointLiteral:
      HexSignificand BinaryExponent FloatTypeSuffixopt
      HexSignificand:
      HexNumeral
      HexNumeral.
      0xHexDigitsopt. HexDigits
      0X HexDigitsopt.HexDigits
      BinaryExponent:
      BinaryExponentIndicator SignedInteger
      BinaryExponentIndicator:
      p
      P
      whereSign,FloatingPointLiteral,HexNumeral,HexDigits,SignedInteger andFloatTypeSuffix are as defined in the lexical structure sections ofThe Java Language Specification, except that underscores are not accepted between digits. Ifs does not have the form of aFloatValue, then aNumberFormatException 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 typefloat 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 ofs is large enough in magnitude (greater than or equal to (MAX_VALUE +ulp(MAX_VALUE)/2), rounding tofloat will result in an infinity and if the exact value ofs is small enough in magnitude (less than or equal toMIN_VALUE/2), rounding to float will result in a zero. Finally, after rounding aFloat object representing thisfloat value is returned.

      Note that trailing format specifiers, specifiers that determine the type of a floating-point literal (1.0f is afloat value;1.0d is adouble value), donot 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 todouble followed bydouble tofloat, isnot equivalent to converting a string directly tofloat. For example, if first converted to an intermediatedouble and then tofloat, the string
      "1.00000017881393421514957253748434595763683319091796875001d"
      results in thefloat value1.0000002f; if the string is converted directly tofloat,1.0000001f results.

      To avoid calling this method on an invalid string and having aNumberFormatException be thrown, the documentation forDouble.valueOf lists a regular expression which can be used to screen the input.

      API Note:
      To interpret localized string representations of a floating-point value, or string representations that have non-ASCII digits, useNumberFormat. For example,
          NumberFormat.getInstance(l).parse(s).floatValue();
      wherel is the desired locale, orLocale.ROOT if locale insensitive., This method corresponds to the convertFromDecimalCharacter and convertFromHexCharacter operations defined in IEEE 754.
      Parameters:
      s - the string to be parsed.
      Returns:
      aFloat object holding the value represented by theString argument.
      Throws:
      NumberFormatException - if the string does not contain a parsable number.
      See Also:
    • valueOf

      public static Float valueOf(float f)
      Returns aFloat instance representing the specifiedfloat value. If a newFloat instance is not required, this method should generally be used in preference to the constructorFloat(float), as this method is likely to yield significantly better space and time performance by caching frequently requested values.
      Parameters:
      f - a float value.
      Returns:
      aFloat instance representingf.
      Since:
      1.5
    • parseFloat

      public static float parseFloat(String s) throwsNumberFormatException
      Returns a newfloat initialized to the value represented by the specifiedString, as performed by thevalueOf method of classFloat.
      Parameters:
      s - the string to be parsed.
      Returns:
      thefloat value represented by the string argument.
      Throws:
      NullPointerException - if the string is null
      NumberFormatException - if the string does not contain a parsablefloat.
      Since:
      1.2
      See Also:
    • isNaN

      public static boolean isNaN(float v)
      Returnstrue if the specified number is a Not-a-Number (NaN) value,false otherwise.
      API Note:
      This method corresponds to the isNaN operation defined in IEEE 754.
      Parameters:
      v - the value to be tested.
      Returns:
      true if the argument is NaN;false otherwise.
    • isInfinite

      public static boolean isInfinite(float v)
      Returnstrue if the specified number is infinitely large in magnitude,false otherwise.
      API Note:
      This method corresponds to the isInfinite operation defined in IEEE 754.
      Parameters:
      v - the value to be tested.
      Returns:
      true if the argument is positive infinity or negative infinity;false otherwise.
    • isFinite

      public static boolean isFinite(float f)
      Returnstrue if the argument is a finite floating-point value; returnsfalse otherwise (for NaN and infinity arguments).
      API Note:
      This method corresponds to the isFinite operation defined in IEEE 754.
      Parameters:
      f - thefloat value to be tested
      Returns:
      true if the argument is a finite floating-point value,false otherwise.
      Since:
      1.8
    • isNaN

      public boolean isNaN()
      Returnstrue if thisFloat value is a Not-a-Number (NaN),false otherwise.
      Returns:
      true if the value represented by this object is NaN;false otherwise.
    • isInfinite

      public boolean isInfinite()
      Returnstrue if thisFloat value is infinitely large in magnitude,false otherwise.
      Returns:
      true if the value represented by this object is positive infinity or negative infinity;false otherwise.
    • toString

      public String toString()
      Returns a string representation of thisFloat object. The primitivefloat value represented by this object is converted to aString exactly as if by the methodtoString of one argument.
      Overrides:
      toString in class Object
      Returns:
      aString representation of this object.
      See Also:
    • byteValue

      public byte byteValue()
      Returns the value of thisFloat as abyte after a narrowing primitive conversion.
      Overrides:
      byteValue in class Number
      Returns:
      thefloat value represented by this object converted to typebyte
      SeeJava Language Specification:
      5.1.3 Narrowing Primitive Conversion
    • shortValue

      public short shortValue()
      Returns the value of thisFloat as ashort after a narrowing primitive conversion.
      Overrides:
      shortValue in class Number
      Returns:
      thefloat value represented by this object converted to typeshort
      SeeJava Language Specification:
      5.1.3 Narrowing Primitive Conversion
      Since:
      1.1
    • intValue

      public int intValue()
      Returns the value of thisFloat as anint after a narrowing primitive conversion.
      Specified by:
      intValue in class Number
      API Note:
      This method corresponds to the convertToIntegerTowardZero operation defined in IEEE 754.
      Returns:
      thefloat value represented by this object converted to typeint
      SeeJava Language Specification:
      5.1.3 Narrowing Primitive Conversion
    • longValue

      public long longValue()
      Returns value of thisFloat as along after a narrowing primitive conversion.
      Specified by:
      longValue in class Number
      API Note:
      This method corresponds to the convertToIntegerTowardZero operation defined in IEEE 754.
      Returns:
      thefloat value represented by this object converted to typelong
      SeeJava Language Specification:
      5.1.3 Narrowing Primitive Conversion
    • floatValue

      public float floatValue()
      Returns thefloat value of thisFloat object.
      Specified by:
      floatValue in class Number
      Returns:
      thefloat value represented by this object
    • doubleValue

      public double doubleValue()
      Returns the value of thisFloat as adouble after a widening primitive conversion.
      Specified by:
      doubleValue in class Number
      API Note:
      This method corresponds to the convertFormat operation defined in IEEE 754.
      Returns:
      thefloat value represented by this object converted to typedouble
      SeeJava Language Specification:
      5.1.2 Widening Primitive Conversion
    • hashCode

      public int hashCode()
      Returns a hash code for thisFloat object. The result is the integer bit representation, exactly as produced by the methodfloatToIntBits(float), of the primitivefloat value represented by thisFloat object.
      Overrides:
      hashCode in class Object
      Returns:
      a hash code value for this object.
      See Also:
    • hashCode

      public static int hashCode(float value)
      Returns a hash code for afloat value; compatible withFloat.hashCode().
      Parameters:
      value - the value to hash
      Returns:
      a hash code value for afloat value.
      Since:
      1.8
    • equals

      public boolean equals(Object obj)
      Compares this object against the specified object. The result istrue if and only if the argument is notnull and is aFloat object that represents afloat with the same value as thefloat represented by this object. For this purpose, twofloat values are considered to be the same if and only if the methodfloatToIntBits(float) returns the identicalint value when applied to each.
      Overrides:
      equals in class Object
      API Note:
      This method is defined in terms offloatToIntBits(float) rather than the== operator onfloat values since the== operator doesnot define an equivalence relation and to satisfy theequals contract an equivalence relation must be implemented; seethis discussion for details of floating-point equality and equivalence.
      Parameters:
      obj - the object to be compared
      Returns:
      true if the objects are the same;false otherwise.
      SeeJava Language Specification:
      15.21.1 Numerical Equality Operators == and !=
      See Also:
    • floatToIntBits

      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 mask0x80000000) represents the sign of the floating-point number. Bits 30-23 (the bits that are selected by the mask0x7f800000) represent the exponent. Bits 22-0 (the bits that are selected by the mask0x007fffff) represent the significand (sometimes called the mantissa) of the floating-point number.

      If the argument is positive infinity, the result is0x7f800000.

      If the argument is negative infinity, the result is0xff800000.

      If the argument is NaN, the result is0x7fc00000.

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

      Parameters:
      value - a floating-point number.
      Returns:
      the bits that represent the floating-point number.
    • floatToRawIntBits

      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 mask0x80000000) represents the sign of the floating-point number. Bits 30-23 (the bits that are selected by the mask0x7f800000) represent the exponent. Bits 22-0 (the bits that are selected by the mask0x007fffff) represent the significand (sometimes called the mantissa) of the floating-point number.

      If the argument is positive infinity, the result is0x7f800000.

      If the argument is negative infinity, the result is0xff800000.

      If the argument is NaN, the result is the integer representing the actual NaN value. Unlike thefloatToIntBits 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 theintBitsToFloat(int) method, will produce a floating-point value the same as the argument tofloatToRawIntBits.

      Parameters:
      value - a floating-point number.
      Returns:
      the bits that represent the floating-point number.
      Since:
      1.3
    • intBitsToFloat

      public static float intBitsToFloat(int bits)
      Returns thefloat 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 is0x7f800000, the result is positive infinity.

      If the argument is0xff800000, the result is negative infinity.

      If the argument is any value in the range0x7f800001 through0x7fffffff or in the range0xff800001 through0xffffffff, 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 theFloat.floatToRawIntBits method.

      In all other cases, lets,e, andm 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 floating-point result equals the value of the mathematical expressions·m·2e-150.

      Note that this method may not be able to return afloat NaN with exactly same bit pattern as theint argument. IEEE 754 distinguishes between two kinds of NaNs, quiet NaNs andsignaling 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. SointBitsToFloat may not be able to return afloat with a signaling NaN bit pattern. Consequently, for someint values,floatToRawIntBits(intBitsToFloat(start)) maynot equalstart. 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.
      Returns:
      thefloat floating-point value with the same bit pattern.
    • float16ToFloat

      public static float float16ToFloat(short floatBinary16)
      Returns thefloat value closest to the numerical value of the argument, a floating-point binary16 value encoded in ashort. The conversion is exact; all binary16 values can be exactly represented infloat. 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 thedouble 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 (JLS4.2.3) for the binary16 format are N = 11 precision bits, K = 5 exponent bits,Emax = 15, andEmin = -14.
      API Note:
      This method corresponds to the convertFormat operation defined in IEEE 754 from the binary16 format to the binary32 format. The operation of this method is analogous to a primitive widening conversion (JLS5.1.2).
      Parameters:
      floatBinary16 - the binary16 value to convert tofloat
      Returns:
      thefloat value closest to the numerical value of the argument, a floating-point binary16 value encoded in ashort
      Since:
      20
    • floatToFloat16

      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 theround 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.
      Thebinary16 format is discussed in more detail in thefloat16ToFloat(short) method.
      API Note:
      This method corresponds to the convertFormat operation defined in IEEE 754 from the binary32 format to the binary16 format. The operation of this method is analogous to a primitive narrowing conversion (JLS5.1.3).
      Parameters:
      f - thefloat value to convert to binary16
      Returns:
      the floating-point binary16 value, encoded in a short, closest in value to the argument
      Since:
      20
    • compareTo

      public int compareTo(Float anotherFloat)
      Compares twoFloat objects numerically. This method imposes a total order onFloat objects with two differences compared to the incomplete order defined by the Java language numerical comparison operators (<, <=, ==, >=, >) onfloat values.
      • A NaN isunordered 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 otherdouble 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 thenatural ordering ofFloat objects imposed by this method isconsistent with equals; seethis discussion for details of floating-point comparison and ordering.
      Specified by:
      compareTo in interface Comparable<Float>
      Parameters:
      anotherFloat - theFloat to be compared.
      Returns:
      the value0 ifanotherFloat is numerically equal to thisFloat; a value less than0 if thisFloat is numerically less thananotherFloat; and a value greater than0 if thisFloat is numerically greater thananotherFloat.
      SeeJava Language Specification:
      15.20.1 Numerical Comparison Operators<,<=,>, and>=
      Since:
      1.2
    • compare

      public static int compare(float f1, float f2)
      Compares the two specifiedfloat 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))
      Parameters:
      f1 - the firstfloat to compare.
      f2 - the secondfloat to compare.
      Returns:
      the value0 iff1 is numerically equal tof2; a value less than0 iff1 is numerically less thanf2; and a value greater than0 iff1 is numerically greater thanf2.
      Since:
      1.4
    • sum

      public static float sum(float a, float b)
      Adds twofloat values together as per the + operator.
      API Note:
      This method corresponds to the addition operation defined in IEEE 754.
      Parameters:
      a - the first operand
      b - the second operand
      Returns:
      the sum ofa andb
      SeeJava Language Specification:
      4.2.4 Floating-Point Operations
      Since:
      1.8
      See Also:
    • max

      public static float max(float a, float b)
      Returns the greater of twofloat values as if by callingMath.max.
      API Note:
      This method corresponds to the maximum operation defined in IEEE 754.
      Parameters:
      a - the first operand
      b - the second operand
      Returns:
      the greater ofa andb
      Since:
      1.8
      See Also:
    • min

      public static float min(float a, float b)
      Returns the smaller of twofloat values as if by callingMath.min.
      API Note:
      This method corresponds to the minimum operation defined in IEEE 754.
      Parameters:
      a - the first operand
      b - the second operand
      Returns:
      the smaller ofa andb
      Since:
      1.8
      See Also:
    • describeConstable

      public Optional<Float> describeConstable()
      Returns anOptional containing the nominal descriptor for this instance, which is the instance itself.
      Specified by:
      describeConstable in interface Constable
      Returns:
      anOptional describing theFloat instance
      Since:
      12
    • resolveConstantDesc

      public Float resolveConstantDesc(MethodHandles.Lookup lookup)
      Resolves this instance as aConstantDesc, the result of which is the instance itself.
      Specified by:
      resolveConstantDesc in interface ConstantDesc
      Parameters:
      lookup - ignored
      Returns:
      theFloat instance
      Since:
      12