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:

Sign_opt DecimalNumeral

Sign_opt 0x HexDigits

Sign_opt 0X HexDigits

Sign_opt # HexDigits

Sign_opt 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