Module java.base
Package java.lang

# Class Byte

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

All Implemented Interfaces:
  `Serializable`, `Comparable<Byte>`, `Constable`

public final class Byte extends Number implements Comparable<Byte>, Constable
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`.

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

Since:
  1.1
See Also:
  - `Number`
  - Serialized Form

## Field Summary

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

## Constructor Summary

Constructors
Constructor
Description
`Byte(byte value)`
Deprecated, for removal: This API element is subject to removal in a future version.
It is rarely appropriate to use this constructor.
`Byte(String s)`
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`
`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 int`
`compareUnsigned(byte x, byte y)`
Compares two `byte` values numerically treating the values as unsigned.
`static Byte`
`decode(String nm)`
Decodes a `String` into a `Byte`.
`Optional<DynamicConstantDesc<Byte>>`
`describeConstable()`
Returns an `Optional` containing the nominal descriptor for this instance.
`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 declared in class java.lang.Object

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

## Field Details

### 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 Details

### Byte

@Deprecated(since="9", forRemoval=true) public Byte(byte 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 factory `valueOf(byte)` is generally a better choice, as it is likely to yield significantly better space and time performance.
Constructs a newly allocated `Byte` object that represents the specified `byte` value.

Parameters:
  `value` - the value to be represented by the `Byte`.

### Byte

@Deprecated(since="9", forRemoval=true) public Byte(String s) throws NumberFormatException
Deprecated, for removal: This API element is subject to removal in a future version.
It is rarely appropriate to use this constructor. Use `parseByte(String)` to convert a string to a `byte` primitive, or use `valueOf(String)` to convert a string to a `Byte` object.
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`.

## Method Details

### 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)`

### describeConstable

public Optional<DynamicConstantDesc<Byte>> describeConstable()
Returns an `Optional` containing the nominal descriptor for this instance.

Specified by:
  `describeConstable` in interface `Constable`
Returns:
  an `Optional` describing the Byte instance
Since:
  15

### 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:

> `Byte.valueOf(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:

> `Byte.valueOf(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 Java Language Specification:
  5.1.2 Widening Primitive Conversion

### 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 Java Language Specification:
  5.1.2 Widening Primitive Conversion

### 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 Java Language Specification:
  5.1.2 Widening Primitive Conversion

### 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 Java Language Specification:
  5.1.2 Widening Primitive Conversion

### 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 Java Language Specification:
  5.1.2 Widening Primitive Conversion

### 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

### compareUnsigned

public static int compareUnsigned(byte x, byte y)
Compares two `byte` values numerically treating the values as unsigned.

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` as unsigned values; and a value greater than `0` if `x > y` as unsigned values
Since:
  9

### 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