Field Summary

Constructor Summary

Method Summary

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:

  • Constant Field Values

• 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:

  • Constant Field Values

• NaN

  public static final float NaN

  A constant holding a Not-a-Number (NaN) value of typefloat. It is equivalent to the value returned byFloat.intBitsToFloat(0x7fc00000).

  See Also:

  • Constant Field Values

• 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:

  • Constant Field Values

• 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:

  • Constant Field Values

• 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:

  • Constant Field Values

• MAX_EXPONENT

  public static final int MAX_EXPONENT

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

  Since:

  1.6

  See Also:

  • Constant Field Values

• MIN_EXPONENT

  public static final int MIN_EXPONENT

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

  Since:

  1.6

  See Also:

  • Constant Field Values

• SIZE

  public static final int SIZE

  The number of bits used to represent afloat value.

  Since:

  1.5

  See Also:

  • Constant Field Values

• BYTES

  public static final int BYTES

  The number of bytes used to represent afloat value.

  Since:

  1.8

  See Also:

  • Constant Field Values

• 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".
    • Ifm is greater than or equal to 10^-3 but less than 10⁷, then it is represented as the integer part ofm, in decimal form with no leading zeroes, followed by '.' ('\u002E'), followed by one or more decimal digits representing the fractional part ofm.
    • Ifm is less than 10^-3 or greater than or equal to 10⁷, then it is represented in so-called "computerized scientific notation." Letn be the unique integer such that 10ⁿ≤m < 10ⁿ⁺¹; then leta be the mathematically exact quotient ofm and 10ⁿ so that 1 ≤a < 10. The magnitude is then represented as the integer part ofa, as a single decimal digit, followed by '.' ('\u002E'), followed by decimal digits representing the fractional part ofa, followed by the letter 'E' ('\u0045'), followed by a representation ofn as a decimal integer, as produced by the methodInteger.toString(int).

  How many digits must be printed for the fractional part ofm ora? 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 typefloat. That is, suppose thatx is the exact mathematical value represented by the decimal representation produced by this method for a finite nonzero argumentf. Thenf must be thefloat value nearest tox; or, if twofloat values are equally close tox, thenf must be one of them and the least significant bit of the significand off must be0.

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

  Parameters:

  f - the float 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 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

  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:

  Sign_optNaN

  Sign_optInfinity

  Sign_opt FloatingPointLiteral

  Sign_opt HexFloatingPointLiteral

  SignedInteger

  HexFloatingPointLiteral:

  HexSignificand BinaryExponent FloatTypeSuffix_opt

  HexSignificand:

  HexNumeral

  HexNumeral.

  0xHexDigits_opt. HexDigits

  0X HexDigits_opt.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.

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

  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.

  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.

• 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:

  • valueOf(String)

• isNaN

  public static boolean isNaN(float v)

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

  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.

  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).

  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:

  • toString(float)

• 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

  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

  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

  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:

  • Object.equals(java.lang.Object)
  • System.identityHashCode(java.lang.Object)

• 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(float)

• 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·2^e-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.

• 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:

      new Float(f1).compareTo(new Float(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.

  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:

  • BinaryOperator

• max

  public static float max(float a, float b)

  Returns the greater of twofloat values as if by callingMath.max.

  Parameters:

  a - the first operand

  b - the second operand

  Returns:

  the greater ofa andb

  Since:

  1.8

  See Also:

  • BinaryOperator

• min

  public static float min(float a, float b)

  Returns the smaller of twofloat values as if by callingMath.min.

  Parameters:

  a - the first operand

  b - the second operand

  Returns:

  the smaller ofa andb

  Since:

  1.8

  See Also:

  • BinaryOperator

• 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