Byte (Java Platform SE 8 )
Keywords: java.lang.Byte class
Date: 2015-11-18

compact1, compact2, compact3
java.lang

## Class Byte

- java.lang.Object
- - java.lang.Number
  - - java.lang.Byte

- All Implemented Interfaces:
    Serializable, Comparable<Byte>

      public final class Byte
      extends Number
      implements Comparable<Byte>

  The `Byte` class wraps a value of primitive type `byte` in an object. An object of type `Byte` contains a single field whose type is `byte`.

  In addition, this class provides several methods for converting a `byte` to a `String` and a `String` to a `byte`, as well as other constants and methods useful when dealing with a `byte`.

  Since:
    JDK1.1
  See Also:
    `Number`, Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `BYTES` The number of bytes used to represent a `byte` value in two's complement binary form.
    `static byte` | `MAX_VALUE` A constant holding the maximum value a `byte` can have, 27-1.
    `static byte` | `MIN_VALUE` A constant holding the minimum value a `byte` can have, -27.
    `static int` | `SIZE` The number of bits used to represent a `byte` value in two's complement binary form.
    `static Class<Byte>` | `TYPE` The `Class` instance representing the primitive type `byte`.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `Byte(byte value)` Constructs a newly allocated `Byte` object that represents the specified `byte` value.
    `Byte(String s)` Constructs a newly allocated `Byte` object that represents the `byte` value indicated by the `String` parameter.

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `byte` | `byteValue()` Returns the value of this `Byte` as a `byte`.
    `static int` | `compare(byte x, byte y)` Compares two `byte` values numerically.
    `int` | `compareTo(Byte anotherByte)` Compares two `Byte` objects numerically.
    `static Byte` | `decode(String nm)` Decodes a `String` into a `Byte`.
    `double` | `doubleValue()` Returns the value of this `Byte` as a `double` after a widening primitive conversion.
    `boolean` | `equals(Object obj)` Compares this object to the specified object.
    `float` | `floatValue()` Returns the value of this `Byte` as a `float` after a widening primitive conversion.
    `int` | `hashCode()` Returns a hash code for this `Byte`; equal to the result of invoking `intValue()`.
    `static int` | `hashCode(byte value)` Returns a hash code for a `byte` value; compatible with `Byte.hashCode()`.
    `int` | `intValue()` Returns the value of this `Byte` as an `int` after a widening primitive conversion.
    `long` | `longValue()` Returns the value of this `Byte` as a `long` after a widening primitive conversion.
    `static byte` | `parseByte(String s)` Parses the string argument as a signed decimal `byte`.
    `static byte` | `parseByte(String s, int radix)` Parses the string argument as a signed `byte` in the radix specified by the second argument.
    `short` | `shortValue()` Returns the value of this `Byte` as a `short` after a widening primitive conversion.
    `String` | `toString()` Returns a `String` object representing this `Byte`'s value.
    `static String` | `toString(byte b)` Returns a new `String` object representing the specified `byte`.
    `static int` | `toUnsignedInt(byte x)` Converts the argument to an `int` by an unsigned conversion.
    `static long` | `toUnsignedLong(byte x)` Converts the argument to a `long` by an unsigned conversion.
    `static Byte` | `valueOf(byte b)` Returns a `Byte` instance representing the specified `byte` value.
    `static Byte` | `valueOf(String s)` Returns a `Byte` object holding the value given by the specified `String`.
    `static Byte` | `valueOf(String s, int radix)` Returns a `Byte` object holding the value extracted from the specified `String` when parsed with the radix given by the second argument.

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

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Field Detail

    - #### MIN_VALUE

          public static final byte MIN_VALUE

      A constant holding the minimum value a `byte` can have, -27.
      See Also:
        Constant Field Values

    - #### MAX_VALUE

          public static final byte MAX_VALUE

      A constant holding the maximum value a `byte` can have, 27-1.
      See Also:
        Constant Field Values

    - #### TYPE

          public static final Class<Byte> TYPE

      The `Class` instance representing the primitive type `byte`.

    - #### SIZE

          public static final int SIZE

      The number of bits used to represent a `byte` value in two's complement binary form.
      Since:
        1.5
      See Also:
        Constant Field Values

    - #### BYTES

          public static final int BYTES

      The number of bytes used to represent a `byte` value in two's complement binary form.
      Since:
        1.8
      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### Byte

          public Byte(byte value)

      Constructs a newly allocated `Byte` object that represents the specified `byte` value.
      Parameters:
        `value` - the value to be represented by the `Byte`.

    - #### Byte

          public Byte(String s)
               throws NumberFormatException

      Constructs a newly allocated `Byte` object that represents the `byte` value indicated by the `String` parameter. The string is converted to a `byte` value in exactly the manner used by the `parseByte` method for radix 10.
      Parameters:
        `s` - the `String` to be converted to a `Byte`
      Throws:
        `NumberFormatException` - If the `String` does not contain a parsable `byte`.
      See Also:
        `parseByte(java.lang.String, int)`

  - ### Method Detail

    - #### toString

          public static String toString(byte b)

      Returns a new `String` object representing the specified `byte`. The radix is assumed to be 10.
      Parameters:
        `b` - the `byte` to be converted
      Returns:
        the string representation of the specified `byte`
      See Also:
        `Integer.toString(int)`

    - #### valueOf

          public static Byte valueOf(byte b)

      Returns a `Byte` instance representing the specified `byte` value. If a new `Byte` instance is not required, this method should generally be used in preference to the constructor `Byte(byte)`, as this method is likely to yield significantly better space and time performance since all byte values are cached.
      Parameters:
        `b` - a byte value.
      Returns:
        a `Byte` instance representing `b`.
      Since:
        1.5

    - #### parseByte

          public static byte parseByte(String s,
                                       int radix)
                                throws NumberFormatException

      Parses the string argument as a signed `byte` in the radix specified by the second argument. The characters in the string must all be digits, of the specified radix (as determined by whether `Character.digit(char, int)` returns a nonnegative value) except that the first character may be an ASCII minus sign `'-'` (`'\u002D'`) to indicate a negative value or an ASCII plus sign `'+'` (`'\u002B'`) to indicate a positive value. The resulting `byte` value is returned.

      An exception of type `NumberFormatException` is thrown if any of the following situations occurs:

      - The first argument is `null` or is a string of length zero.
      - The radix is either smaller than `Character.MIN_RADIX` or larger than `Character.MAX_RADIX`.
      - Any character of the string is not a digit of the specified radix, except that the first character may be a minus sign `'-'` (`'\u002D'`) or plus sign `'+'` (`'\u002B'`) provided that the string is longer than length 1.
      - The value represented by the string is not a value of type `byte`.
      Parameters:
        `s` - the `String` containing the `byte` representation to be parsed
        `radix` - the radix to be used while parsing `s`
      Returns:
        the `byte` value represented by the string argument in the specified radix
      Throws:
        `NumberFormatException` - If the string does not contain a parsable `byte`.

    - #### parseByte

          public static byte parseByte(String s)
                                throws NumberFormatException

      Parses the string argument as a signed decimal `byte`. The characters in the string must all be decimal digits, except that the first character may be an ASCII minus sign `'-'` (`'\u002D'`) to indicate a negative value or an ASCII plus sign `'+'` (`'\u002B'`) to indicate a positive value. The resulting `byte` value is returned, exactly as if the argument and the radix 10 were given as arguments to the `parseByte(java.lang.String, int)` method.
      Parameters:
        `s` - a `String` containing the `byte` representation to be parsed
      Returns:
        the `byte` value represented by the argument in decimal
      Throws:
        `NumberFormatException` - if the string does not contain a parsable `byte`.

    - #### valueOf

          public static Byte valueOf(String s,
                                     int radix)
                              throws NumberFormatException

      Returns a `Byte` object holding the value extracted from the specified `String` when parsed with the radix given by the second argument. The first argument is interpreted as representing a signed `byte` in the radix specified by the second argument, exactly as if the argument were given to the `parseByte(java.lang.String, int)` method. The result is a `Byte` object that represents the `byte` value specified by the string.

      In other words, this method returns a `Byte` object equal to the value of:

      > `new Byte(Byte.parseByte(s, radix))`

      Parameters:
        `s` - the string to be parsed
        `radix` - the radix to be used in interpreting `s`
      Returns:
        a `Byte` object holding the value represented by the string argument in the specified radix.
      Throws:
        `NumberFormatException` - If the `String` does not contain a parsable `byte`.

    - #### valueOf

          public static Byte valueOf(String s)
                              throws NumberFormatException

      Returns a `Byte` object holding the value given by the specified `String`. The argument is interpreted as representing a signed decimal `byte`, exactly as if the argument were given to the `parseByte(java.lang.String)` method. The result is a `Byte` object that represents the `byte` value specified by the string.

      In other words, this method returns a `Byte` object equal to the value of:

      > `new Byte(Byte.parseByte(s))`

      Parameters:
        `s` - the string to be parsed
      Returns:
        a `Byte` object holding the value represented by the string argument
      Throws:
        `NumberFormatException` - If the `String` does not contain a parsable `byte`.

    - #### decode

          public static Byte decode(String nm)
                             throws NumberFormatException

      Decodes a `String` into a `Byte`. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:

      > DecodableString:
      >   Signopt DecimalNumeral
      >   Signopt `0x` HexDigits
      >   Signopt `0X` HexDigits
      >   Signopt `#` HexDigits
      >   Signopt `0` OctalDigits
      > Sign:
      >   `-`
      >   `+`

      DecimalNumeral, HexDigits, and OctalDigits are as defined in section 3.10.1 of The Java™ Language Specification, except that underscores are not accepted between digits.

      The sequence of characters following an optional sign and/or radix specifier ("`0x`", "`0X`", "`#`", or leading zero) is parsed as by the `Byte.parseByte` method with the indicated radix (10, 16, or 8). This sequence of characters must represent a positive value or a `NumberFormatException` will be thrown. The result is negated if first character of the specified `String` is the minus sign. No whitespace characters are permitted in the `String`.

      Parameters:
        `nm` - the `String` to decode.
      Returns:
        a `Byte` object holding the `byte` value represented by `nm`
      Throws:
        `NumberFormatException` - if the `String` does not contain a parsable `byte`.
      See Also:
        `parseByte(java.lang.String, int)`

    - #### byteValue

          public byte byteValue()

      Returns the value of this `Byte` as a `byte`.
      Overrides:
        `byteValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `byte`.

    - #### shortValue

          public short shortValue()

      Returns the value of this `Byte` as a `short` after a widening primitive conversion.
      Overrides:
        `shortValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `short`.
      See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions

    - #### intValue

          public int intValue()

      Returns the value of this `Byte` as an `int` after a widening primitive conversion.
      Specified by:
        `intValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `int`.
      See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions

    - #### longValue

          public long longValue()

      Returns the value of this `Byte` as a `long` after a widening primitive conversion.
      Specified by:
        `longValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `long`.
      See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions

    - #### floatValue

          public float floatValue()

      Returns the value of this `Byte` as a `float` after a widening primitive conversion.
      Specified by:
        `floatValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `float`.
      See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions

    - #### doubleValue

          public double doubleValue()

      Returns the value of this `Byte` as a `double` after a widening primitive conversion.
      Specified by:
        `doubleValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `double`.
      See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions

    - #### toString

          public String toString()

      Returns a `String` object representing this `Byte`'s value. The value is converted to signed decimal representation and returned as a string, exactly as if the `byte` value were given as an argument to the `toString(byte)` method.
      Overrides:
        `toString` in class `Object`
      Returns:
        a string representation of the value of this object in base 10.

    - #### hashCode

          public int hashCode()

      Returns a hash code for this `Byte`; equal to the result of invoking `intValue()`.
      Overrides:
        `hashCode` in class `Object`
      Returns:
        a hash code value for this `Byte`
      See Also:
        `Object.equals(java.lang.Object)`, `System.identityHashCode(java.lang.Object)`

    - #### hashCode

          public static int hashCode(byte value)

      Returns a hash code for a `byte` value; compatible with `Byte.hashCode()`.
      Parameters:
        `value` - the value to hash
      Returns:
        a hash code value for a `byte` value.
      Since:
        1.8

    - #### equals

          public boolean equals(Object obj)

      Compares this object to the specified object. The result is `true` if and only if the argument is not `null` and is a `Byte` object that contains the same `byte` value as this object.
      Overrides:
        `equals` in class `Object`
      Parameters:
        `obj` - the object to compare with
      Returns:
        `true` if the objects are the same; `false` otherwise.
      See Also:
        `Object.hashCode()`, `HashMap`

    - #### compareTo

          public int compareTo(Byte anotherByte)

      Compares two `Byte` objects numerically.
      Specified by:
        `compareTo` in interface `Comparable<Byte>`
      Parameters:
        `anotherByte` - the `Byte` to be compared.
      Returns:
        the value `0` if this `Byte` is equal to the argument `Byte`; a value less than `0` if this `Byte` is numerically less than the argument `Byte`; and a value greater than `0` if this `Byte` is numerically greater than the argument `Byte` (signed comparison).
      Since:
        1.2

    - #### compare

          public static int compare(byte x,
                                    byte y)

      Compares two `byte` values numerically. The value returned is identical to what would be returned by:

              Byte.valueOf(x).compareTo(Byte.valueOf(y))

      Parameters:
        `x` - the first `byte` to compare
        `y` - the second `byte` to compare
      Returns:
        the value `0` if `x == y`; a value less than `0` if `x < y`; and a value greater than `0` if `x > y`
      Since:
        1.7

    - #### toUnsignedInt

          public static int toUnsignedInt(byte x)

      Converts the argument to an `int` by an unsigned conversion. In an unsigned conversion to an `int`, the high-order 24 bits of the `int` are zero and the low-order 8 bits are equal to the bits of the `byte` argument. Consequently, zero and positive `byte` values are mapped to a numerically equal `int` value and negative `byte` values are mapped to an `int` value equal to the input plus 28.
      Parameters:
        `x` - the value to convert to an unsigned `int`
      Returns:
        the argument converted to `int` by an unsigned conversion
      Since:
        1.8

    - #### toUnsignedLong

          public static long toUnsignedLong(byte x)

      Converts the argument to a `long` by an unsigned conversion. In an unsigned conversion to a `long`, the high-order 56 bits of the `long` are zero and the low-order 8 bits are equal to the bits of the `byte` argument. Consequently, zero and positive `byte` values are mapped to a numerically equal `long` value and negative `byte` values are mapped to a `long` value equal to the input plus 28.
      Parameters:
        `x` - the value to convert to an unsigned `long`
      Returns:
        the argument converted to `long` by an unsigned conversion
      Since:
        1.8

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