Module java.base
Package java.lang

# Class Integer

java.lang.Object
java.lang.Number
java.lang.Integer

All Implemented Interfaces:
  `Serializable`, `Comparable<Integer>`, `Constable`, `ConstantDesc`

public final class Integer extends Number implements Comparable<Integer>, Constable, ConstantDesc
The `Integer` class wraps a value of the primitive type `int` in an object. An object of type `Integer` contains a single field whose type is `int`.

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

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.

Implementation note: The implementations of the "bit twiddling" methods (such as `highestOneBit` and `numberOfTrailingZeros`) are based on material from Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002).

Since:
  1.0
See Also:
  - Serialized Form

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final int`
  `BYTES`
  The number of bytes used to represent an `int` value in two's complement binary form.
  `static final int`
  `MAX_VALUE`
  A constant holding the maximum value an `int` can have, 231-1.
  `static final int`
  `MIN_VALUE`
  A constant holding the minimum value an `int` can have, -231.
  `static final int`
  `SIZE`
  The number of bits used to represent an `int` value in two's complement binary form.
  `static final Class<Integer>`
  `TYPE`
  The `Class` instance representing the primitive type `int`.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Integer(int value)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  It is rarely appropriate to use this constructor.
  `Integer(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
  `static int`
  `bitCount(int i)`
  Returns the number of one-bits in the two's complement binary representation of the specified `int` value.
  `byte`
  `byteValue()`
  Returns the value of this `Integer` as a `byte` after a narrowing primitive conversion.
  `static int`
  `compare(int x, int y)`
  Compares two `int` values numerically.
  `int`
  `compareTo(Integer anotherInteger)`
  Compares two `Integer` objects numerically.
  `static int`
  `compareUnsigned(int x, int y)`
  Compares two `int` values numerically treating the values as unsigned.
  `static int`
  `compress(int i, int mask)`
  Returns the value obtained by compressing the bits of the specified `int` value, `i`, in accordance with the specified bit mask.
  `static Integer`
  `decode(String nm)`
  Decodes a `String` into an `Integer`.
  `Optional<Integer>`
  `describeConstable()`
  Returns an `Optional` containing the nominal descriptor for this instance, which is the instance itself.
  `static int`
  `divideUnsigned(int dividend, int divisor)`
  Returns the unsigned quotient of dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
  `double`
  `doubleValue()`
  Returns the value of this `Integer` as a `double` after a widening primitive conversion.
  `boolean`
  `equals(Object obj)`
  Compares this object to the specified object.
  `static int`
  `expand(int i, int mask)`
  Returns the value obtained by expanding the bits of the specified `int` value, `i`, in accordance with the specified bit mask.
  `float`
  `floatValue()`
  Returns the value of this `Integer` as a `float` after a widening primitive conversion.
  `static Integer`
  `getInteger(String nm)`
  Determines the integer value of the system property with the specified name.
  `static Integer`
  `getInteger(String nm, int val)`
  Determines the integer value of the system property with the specified name.
  `static Integer`
  `getInteger(String nm, Integer val)`
  Returns the integer value of the system property with the specified name.
  `int`
  `hashCode()`
  Returns a hash code for this `Integer`.
  `static int`
  `hashCode(int value)`
  Returns a hash code for an `int` value; compatible with `Integer.hashCode()`.
  `static int`
  `highestOneBit(int i)`
  Returns an `int` value with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specified `int` value.
  `int`
  `intValue()`
  Returns the value of this `Integer` as an `int`.
  `long`
  `longValue()`
  Returns the value of this `Integer` as a `long` after a widening primitive conversion.
  `static int`
  `lowestOneBit(int i)`
  Returns an `int` value with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specified `int` value.
  `static int`
  `max(int a, int b)`
  Returns the greater of two `int` values as if by calling `Math.max`.
  `static int`
  `min(int a, int b)`
  Returns the smaller of two `int` values as if by calling `Math.min`.
  `static int`
  `numberOfLeadingZeros(int i)`
  Returns the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specified `int` value.
  `static int`
  `numberOfTrailingZeros(int i)`
  Returns the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specified `int` value.
  `static int`
  `parseInt(CharSequence s, int beginIndex, int endIndex, int radix)`
  Parses the `CharSequence` argument as a signed `int` in the specified `radix`, beginning at the specified `beginIndex` and extending to `endIndex - 1`.
  `static int`
  `parseInt(String s)`
  Parses the string argument as a signed decimal integer.
  `static int`
  `parseInt(String s, int radix)`
  Parses the string argument as a signed integer in the radix specified by the second argument.
  `static int`
  `parseUnsignedInt(CharSequence s, int beginIndex, int endIndex, int radix)`
  Parses the `CharSequence` argument as an unsigned `int` in the specified `radix`, beginning at the specified `beginIndex` and extending to `endIndex - 1`.
  `static int`
  `parseUnsignedInt(String s)`
  Parses the string argument as an unsigned decimal integer.
  `static int`
  `parseUnsignedInt(String s, int radix)`
  Parses the string argument as an unsigned integer in the radix specified by the second argument.
  `static int`
  `remainderUnsigned(int dividend, int divisor)`
  Returns the unsigned remainder from dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
  `Integer`
  `resolveConstantDesc(MethodHandles.Lookup lookup)`
  Resolves this instance as a `ConstantDesc`, the result of which is the instance itself.
  `static int`
  `reverse(int i)`
  Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified `int` value.
  `static int`
  `reverseBytes(int i)`
  Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified `int` value.
  `static int`
  `rotateLeft(int i, int distance)`
  Returns the value obtained by rotating the two's complement binary representation of the specified `int` value left by the specified number of bits.
  `static int`
  `rotateRight(int i, int distance)`
  Returns the value obtained by rotating the two's complement binary representation of the specified `int` value right by the specified number of bits.
  `short`
  `shortValue()`
  Returns the value of this `Integer` as a `short` after a narrowing primitive conversion.
  `static int`
  `signum(int i)`
  Returns the signum function of the specified `int` value.
  `static int`
  `sum(int a, int b)`
  Adds two integers together as per the + operator.
  `static String`
  `toBinaryString(int i)`
  Returns a string representation of the integer argument as an unsigned integer in base 2.
  `static String`
  `toHexString(int i)`
  Returns a string representation of the integer argument as an unsigned integer in base 16.
  `static String`
  `toOctalString(int i)`
  Returns a string representation of the integer argument as an unsigned integer in base 8.
  `String`
  `toString()`
  Returns a `String` object representing this `Integer`'s value.
  `static String`
  `toString(int i)`
  Returns a `String` object representing the specified integer.
  `static String`
  `toString(int i, int radix)`
  Returns a string representation of the first argument in the radix specified by the second argument.
  `static long`
  `toUnsignedLong(int x)`
  Converts the argument to a `long` by an unsigned conversion.
  `static String`
  `toUnsignedString(int i)`
  Returns a string representation of the argument as an unsigned decimal value.
  `static String`
  `toUnsignedString(int i, int radix)`
  Returns a string representation of the first argument as an unsigned integer value in the radix specified by the second argument.
  `static Integer`
  `valueOf(int i)`
  Returns an `Integer` instance representing the specified `int` value.
  `static Integer`
  `valueOf(String s)`
  Returns an `Integer` object holding the value of the specified `String`.
  `static Integer`
  `valueOf(String s, int radix)`
  Returns an `Integer` 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

    @Native public static final int MIN_VALUE
    A constant holding the minimum value an `int` can have, -231.
    See Also:
      - Constant Field Values

  - ### MAX_VALUE

    @Native public static final int MAX_VALUE
    A constant holding the maximum value an `int` can have, 231-1.
    See Also:
      - Constant Field Values

  - ### TYPE

    public static final Class<Integer> TYPE
    The `Class` instance representing the primitive type `int`.
    Since:
      1.1

  - ### SIZE

    @Native public static final int SIZE
    The number of bits used to represent an `int` 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 an `int` value in two's complement binary form.
    Since:
      1.8
    See Also:
      - Constant Field Values

- ## Constructor Details

  - ### Integer

    @Deprecated(since="9", forRemoval=true) public Integer(int 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(int)` is generally a better choice, as it is likely to yield significantly better space and time performance.
    Constructs a newly allocated `Integer` object that represents the specified `int` value.
    Parameters:
      `value` - the value to be represented by the `Integer` object.

  - ### Integer

    @Deprecated(since="9", forRemoval=true) public Integer(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 `parseInt(String)` to convert a string to a `int` primitive, or use `valueOf(String)` to convert a string to an `Integer` object.
    Constructs a newly allocated `Integer` object that represents the `int` value indicated by the `String` parameter. The string is converted to an `int` value in exactly the manner used by the `parseInt` method for radix 10.
    Parameters:
      `s` - the `String` to be converted to an `Integer`.
    Throws:
      `NumberFormatException` - if the `String` does not contain a parsable integer.

- ## Method Details

  - ### toString

    public static String toString(int i, int radix)
    Returns a string representation of the first argument in the radix specified by the second argument.

    If the radix is smaller than `Character.MIN_RADIX` or larger than `Character.MAX_RADIX`, then the radix `10` is used instead.

    If the first argument is negative, the first element of the result is the ASCII minus character `'-'` (`'\u002D'`). If the first argument is not negative, no sign character appears in the result.

    The remaining characters of the result represent the magnitude of the first argument. If the magnitude is zero, it is represented by a single zero character `'0'` (`'\u0030'`); otherwise, the first character of the representation of the magnitude will not be the zero character. The following ASCII characters are used as digits:

    > `0123456789abcdefghijklmnopqrstuvwxyz`

    These are `'\u0030'` through `'\u0039'` and `'\u0061'` through `'\u007A'`. If `radix` is N, then the first N of these characters are used as radix-N digits in the order shown. Thus, the digits for hexadecimal (radix 16) are `0123456789abcdef`. If uppercase letters are desired, the `String.toUpperCase()` method may be called on the result:

    > `Integer.toString(n, 16).toUpperCase()`

    Parameters:
      `i` - an integer to be converted to a string.
      `radix` - the radix to use in the string representation.
    Returns:
      a string representation of the argument in the specified radix.
    See Also:
      - `Character.MAX_RADIX`
      - `Character.MIN_RADIX`

  - ### toUnsignedString

    public static String toUnsignedString(int i, int radix)
    Returns a string representation of the first argument as an unsigned integer value in the radix specified by the second argument.

    If the radix is smaller than `Character.MIN_RADIX` or larger than `Character.MAX_RADIX`, then the radix `10` is used instead.

    Note that since the first argument is treated as an unsigned value, no leading sign character is printed.

    If the magnitude is zero, it is represented by a single zero character `'0'` (`'\u0030'`); otherwise, the first character of the representation of the magnitude will not be the zero character.

    The behavior of radixes and the characters used as digits are the same as `toString`.

    Parameters:
      `i` - an integer to be converted to an unsigned string.
      `radix` - the radix to use in the string representation.
    Returns:
      an unsigned string representation of the argument in the specified radix.
    Since:
      1.8
    See Also:
      - `toString(int, int)`

  - ### toHexString

    public static String toHexString(int i)
    Returns a string representation of the integer argument as an unsigned integer in base 16.

    The unsigned integer value is the argument plus 232 if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in hexadecimal (base 16) with no extra leading `0`s.

    The value of the argument can be recovered from the returned string `s` by calling `Integer.parseUnsignedInt(s, 16)`.

    If the unsigned magnitude is zero, it is represented by a single zero character `'0'` (`'\u0030'`); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The following characters are used as hexadecimal digits:

    > `0123456789abcdef`

    These are the characters `'\u0030'` through `'\u0039'` and `'\u0061'` through `'\u0066'`. If uppercase letters are desired, the `String.toUpperCase()` method may be called on the result:

    > `Integer.toHexString(n).toUpperCase()`

    API Note:
      The `HexFormat` class provides formatting and parsing of byte arrays and primitives to return a string or adding to an `Appendable`. `HexFormat` formats and parses uppercase or lowercase hexadecimal characters, with leading zeros and for byte arrays includes for each byte a delimiter, prefix, and suffix.
    Parameters:
      `i` - an integer to be converted to a string.
    Returns:
      the string representation of the unsigned integer value represented by the argument in hexadecimal (base 16).
    Since:
      1.0.2
    See Also:
      - `HexFormat`
      - `parseUnsignedInt(String, int)`
      - `toUnsignedString(int, int)`

  - ### toOctalString

    public static String toOctalString(int i)
    Returns a string representation of the integer argument as an unsigned integer in base 8.

    The unsigned integer value is the argument plus 232 if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in octal (base 8) with no extra leading `0`s.

    The value of the argument can be recovered from the returned string `s` by calling `Integer.parseUnsignedInt(s, 8)`.

    If the unsigned magnitude is zero, it is represented by a single zero character `'0'` (`'\u0030'`); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The following characters are used as octal digits:

    > `01234567`

    These are the characters `'\u0030'` through `'\u0037'`.
    Parameters:
      `i` - an integer to be converted to a string.
    Returns:
      the string representation of the unsigned integer value represented by the argument in octal (base 8).
    Since:
      1.0.2
    See Also:
      - `parseUnsignedInt(String, int)`
      - `toUnsignedString(int, int)`

  - ### toBinaryString

    public static String toBinaryString(int i)
    Returns a string representation of the integer argument as an unsigned integer in base 2.

    The unsigned integer value is the argument plus 232 if the argument is negative; otherwise it is equal to the argument. This value is converted to a string of ASCII digits in binary (base 2) with no extra leading `0`s.

    The value of the argument can be recovered from the returned string `s` by calling `Integer.parseUnsignedInt(s, 2)`.

    If the unsigned magnitude is zero, it is represented by a single zero character `'0'` (`'\u0030'`); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The characters `'0'` (`'\u0030'`) and `'1'` (`'\u0031'`) are used as binary digits.

    Parameters:
      `i` - an integer to be converted to a string.
    Returns:
      the string representation of the unsigned integer value represented by the argument in binary (base 2).
    Since:
      1.0.2
    See Also:
      - `parseUnsignedInt(String, int)`
      - `toUnsignedString(int, int)`

  - ### toString

    public static String toString(int i)
    Returns a `String` object representing the specified integer. The argument is converted to signed decimal representation and returned as a string, exactly as if the argument and radix 10 were given as arguments to the `toString(int, int)` method.
    Parameters:
      `i` - an integer to be converted.
    Returns:
      a string representation of the argument in base 10.

  - ### toUnsignedString

    public static String toUnsignedString(int i)
    Returns a string representation of the argument as an unsigned decimal value. The argument is converted to unsigned decimal representation and returned as a string exactly as if the argument and radix 10 were given as arguments to the `toUnsignedString(int, int)` method.
    Parameters:
      `i` - an integer to be converted to an unsigned string.
    Returns:
      an unsigned string representation of the argument.
    Since:
      1.8
    See Also:
      - `toUnsignedString(int, int)`

  - ### parseInt

    public static int parseInt(String s, int radix) throws NumberFormatException
    Parses the string argument as a signed integer 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 integer 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 `int`.

    Examples:

    >      parseInt("0", 10) returns 0
    >      parseInt("473", 10) returns 473
    >      parseInt("+42", 10) returns 42
    >      parseInt("-0", 10) returns 0
    >      parseInt("-FF", 16) returns -255
    >      parseInt("1100110", 2) returns 102
    >      parseInt("2147483647", 10) returns 2147483647
    >      parseInt("-2147483648", 10) returns -2147483648
    >      parseInt("2147483648", 10) throws a NumberFormatException
    >      parseInt("99", 8) throws a NumberFormatException
    >      parseInt("Kona", 10) throws a NumberFormatException
    >      parseInt("Kona", 27) returns 411787

    Parameters:
      `s` - the `String` containing the integer representation to be parsed
      `radix` - the radix to be used while parsing `s`.
    Returns:
      the integer represented by the string argument in the specified radix.
    Throws:
      `NumberFormatException` - if the `String` does not contain a parsable `int`.

  - ### parseInt

    public static int parseInt(CharSequence s, int beginIndex, int endIndex, int radix) throws NumberFormatException
    Parses the `CharSequence` argument as a signed `int` in the specified `radix`, beginning at the specified `beginIndex` and extending to `endIndex - 1`.

    The method does not take steps to guard against the `CharSequence` being mutated while parsing.

    Parameters:
      `s` - the `CharSequence` containing the `int` representation to be parsed
      `beginIndex` - the beginning index, inclusive.
      `endIndex` - the ending index, exclusive.
      `radix` - the radix to be used while parsing `s`.
    Returns:
      the signed `int` represented by the subsequence in the specified radix.
    Throws:
      `NullPointerException` - if `s` is null.
      `IndexOutOfBoundsException` - if `beginIndex` is negative, or if `beginIndex` is greater than `endIndex` or if `endIndex` is greater than `s.length()`.
      `NumberFormatException` - if the `CharSequence` does not contain a parsable `int` in the specified `radix`, or if `radix` is either smaller than `Character.MIN_RADIX` or larger than `Character.MAX_RADIX`.
    Since:
      9

  - ### parseInt

    public static int parseInt(String s) throws NumberFormatException
    Parses the string argument as a signed decimal integer. 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 integer value is returned, exactly as if the argument and the radix 10 were given as arguments to the `parseInt(java.lang.String, int)` method.
    Parameters:
      `s` - a `String` containing the `int` representation to be parsed
    Returns:
      the integer value represented by the argument in decimal.
    Throws:
      `NumberFormatException` - if the string does not contain a parsable integer.

  - ### parseUnsignedInt

    public static int parseUnsignedInt(String s, int radix) throws NumberFormatException
    Parses the string argument as an unsigned integer in the radix specified by the second argument. An unsigned integer maps the values usually associated with negative numbers to positive numbers larger than `MAX_VALUE`. 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 plus sign `'+'` (`'\u002B'`). The resulting integer 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 plus sign `'+'` (`'\u002B'`) provided that the string is longer than length 1.
    - The value represented by the string is larger than the largest unsigned `int`, 232-1.
    Parameters:
      `s` - the `String` containing the unsigned integer representation to be parsed
      `radix` - the radix to be used while parsing `s`.
    Returns:
      the integer represented by the string argument in the specified radix.
    Throws:
      `NumberFormatException` - if the `String` does not contain a parsable `int`.
    Since:
      1.8

  - ### parseUnsignedInt

    public static int parseUnsignedInt(CharSequence s, int beginIndex, int endIndex, int radix) throws NumberFormatException
    Parses the `CharSequence` argument as an unsigned `int` in the specified `radix`, beginning at the specified `beginIndex` and extending to `endIndex - 1`.

    The method does not take steps to guard against the `CharSequence` being mutated while parsing.

    Parameters:
      `s` - the `CharSequence` containing the unsigned `int` representation to be parsed
      `beginIndex` - the beginning index, inclusive.
      `endIndex` - the ending index, exclusive.
      `radix` - the radix to be used while parsing `s`.
    Returns:
      the unsigned `int` represented by the subsequence in the specified radix.
    Throws:
      `NullPointerException` - if `s` is null.
      `IndexOutOfBoundsException` - if `beginIndex` is negative, or if `beginIndex` is greater than `endIndex` or if `endIndex` is greater than `s.length()`.
      `NumberFormatException` - if the `CharSequence` does not contain a parsable unsigned `int` in the specified `radix`, or if `radix` is either smaller than `Character.MIN_RADIX` or larger than `Character.MAX_RADIX`.
    Since:
      9

  - ### parseUnsignedInt

    public static int parseUnsignedInt(String s) throws NumberFormatException
    Parses the string argument as an unsigned decimal integer. The characters in the string must all be decimal digits, except that the first character may be an ASCII plus sign `'+'` (`'\u002B'`). The resulting integer value is returned, exactly as if the argument and the radix 10 were given as arguments to the `parseUnsignedInt(java.lang.String, int)` method.
    Parameters:
      `s` - a `String` containing the unsigned `int` representation to be parsed
    Returns:
      the unsigned integer value represented by the argument in decimal.
    Throws:
      `NumberFormatException` - if the string does not contain a parsable unsigned integer.
    Since:
      1.8

  - ### valueOf

    public static Integer valueOf(String s, int radix) throws NumberFormatException
    Returns an `Integer` 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 integer in the radix specified by the second argument, exactly as if the arguments were given to the `parseInt(java.lang.String, int)` method. The result is an `Integer` object that represents the integer value specified by the string.

    In other words, this method returns an `Integer` object equal to the value of:

    > `Integer.valueOf(Integer.parseInt(s, radix))`

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

  - ### valueOf

    public static Integer valueOf(String s) throws NumberFormatException
    Returns an `Integer` object holding the value of the specified `String`. The argument is interpreted as representing a signed decimal integer, exactly as if the argument were given to the `parseInt(java.lang.String)` method. The result is an `Integer` object that represents the integer value specified by the string.

    In other words, this method returns an `Integer` object equal to the value of:

    > `Integer.valueOf(Integer.parseInt(s))`

    Parameters:
      `s` - the string to be parsed.
    Returns:
      an `Integer` object holding the value represented by the string argument.
    Throws:
      `NumberFormatException` - if the string cannot be parsed as an integer.

  - ### valueOf

    public static Integer valueOf(int i)
    Returns an `Integer` instance representing the specified `int` value. If a new `Integer` instance is not required, this method should generally be used in preference to the constructor `Integer(int)`, as this method is likely to yield significantly better space and time performance by caching frequently requested values. This method will always cache values in the range -128 to 127, inclusive, and may cache other values outside of this range.
    Parameters:
      `i` - an `int` value.
    Returns:
      an `Integer` instance representing `i`.
    Since:
      1.5

  - ### byteValue

    public byte byteValue()
    Returns the value of this `Integer` as a `byte` after a narrowing primitive conversion.
    Overrides:
      `byteValue` in class `Number`
    Returns:
      the numeric value represented by this object after conversion to type `byte`.
    See Java Language Specification:
      5.1.3 Narrowing Primitive Conversion

  - ### shortValue

    public short shortValue()
    Returns the value of this `Integer` as a `short` after a narrowing primitive conversion.
    Overrides:
      `shortValue` in class `Number`
    Returns:
      the numeric value represented by this object after conversion to type `short`.
    See Java Language Specification:
      5.1.3 Narrowing Primitive Conversion

  - ### intValue

    public int intValue()
    Returns the value of this `Integer` as an `int`.
    Specified by:
      `intValue` in class `Number`
    Returns:
      the numeric value represented by this object after conversion to type `int`.

  - ### longValue

    public long longValue()
    Returns the value of this `Integer` 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
    See Also:
      - `toUnsignedLong(int)`

  - ### floatValue

    public float floatValue()
    Returns the value of this `Integer` 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 `Integer` 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 `Integer`'s value. The value is converted to signed decimal representation and returned as a string, exactly as if the integer value were given as an argument to the `toString(int)` 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 `Integer`.
    Overrides:
      `hashCode` in class `Object`
    Returns:
      a hash code value for this object, equal to the primitive `int` value represented by this `Integer` object.
    See Also:
      - `Object.equals(java.lang.Object)`
      - `System.identityHashCode(java.lang.Object)`

  - ### hashCode

    public static int hashCode(int value)
    Returns a hash code for an `int` value; compatible with `Integer.hashCode()`.
    Parameters:
      `value` - the value to hash
    Returns:
      a hash code value for an `int` 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 an `Integer` object that contains the same `int` 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`

  - ### getInteger

    public static Integer getInteger(String nm)
    Determines the integer value of the system property with the specified name.

    The first argument is treated as the name of a system property. System properties are accessible through the `System.getProperty(java.lang.String)` method. The string value of this property is then interpreted as an integer value using the grammar supported by `decode` and an `Integer` object representing this value is returned.

    If there is no property with the specified name, if the specified name is empty or `null`, or if the property does not have the correct numeric format, then `null` is returned.

    In other words, this method returns an `Integer` object equal to the value of:

    > `getInteger(nm, null)`

    Parameters:
      `nm` - property name.
    Returns:
      the `Integer` value of the property.
    Throws:
      `SecurityException` - for the same reasons as `System.getProperty`
    See Also:
      - `System.getProperty(java.lang.String)`
      - `System.getProperty(java.lang.String, java.lang.String)`

  - ### getInteger

    public static Integer getInteger(String nm, int val)
    Determines the integer value of the system property with the specified name.

    The first argument is treated as the name of a system property. System properties are accessible through the `System.getProperty(java.lang.String)` method. The string value of this property is then interpreted as an integer value using the grammar supported by `decode` and an `Integer` object representing this value is returned.

    The second argument is the default value. An `Integer` object that represents the value of the second argument is returned if there is no property of the specified name, if the property does not have the correct numeric format, or if the specified name is empty or `null`.

    In other words, this method returns an `Integer` object equal to the value of:

    > `getInteger(nm, Integer.valueOf(val))`

    but in practice it may be implemented in a manner such as:

    >      Integer result = getInteger(nm, null);
    >      return (result == null) ? Integer.valueOf(val) : result;

    to avoid the unnecessary allocation of an `Integer` object when the default value is not needed.
    Parameters:
      `nm` - property name.
      `val` - default value.
    Returns:
      the `Integer` value of the property.
    Throws:
      `SecurityException` - for the same reasons as `System.getProperty`
    See Also:
      - `System.getProperty(java.lang.String)`
      - `System.getProperty(java.lang.String, java.lang.String)`

  - ### getInteger

    public static Integer getInteger(String nm, Integer val)
    Returns the integer value of the system property with the specified name. The first argument is treated as the name of a system property. System properties are accessible through the `System.getProperty(java.lang.String)` method. The string value of this property is then interpreted as an integer value, as per the `decode` method, and an `Integer` object representing this value is returned; in summary:
    - If the property value begins with the two ASCII characters `0x` or the ASCII character `#`, not followed by a minus sign, then the rest of it is parsed as a hexadecimal integer exactly as by the method `valueOf(java.lang.String, int)` with radix 16.
    - If the property value begins with the ASCII character `0` followed by another character, it is parsed as an octal integer exactly as by the method `valueOf(java.lang.String, int)` with radix 8.
    - Otherwise, the property value is parsed as a decimal integer exactly as by the method `valueOf(java.lang.String, int)` with radix 10.

    The second argument is the default value. The default value is returned if there is no property of the specified name, if the property does not have the correct numeric format, or if the specified name is empty or `null`.

    Parameters:
      `nm` - property name.
      `val` - default value.
    Returns:
      the `Integer` value of the property.
    Throws:
      `SecurityException` - for the same reasons as `System.getProperty`
    See Also:
      - `System.getProperty(java.lang.String)`
      - `System.getProperty(java.lang.String, java.lang.String)`

  - ### decode

    public static Integer decode(String nm) throws NumberFormatException
    Decodes a `String` into an `Integer`. 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 `Integer.parseInt` 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:
      an `Integer` object holding the `int` value represented by `nm`
    Throws:
      `NumberFormatException` - if the `String` does not contain a parsable integer.
    See Also:
      - `parseInt(java.lang.String, int)`

  - ### compareTo

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

  - ### compare

    public static int compare(int x, int y)
    Compares two `int` values numerically. The value returned is identical to what would be returned by:

            Integer.valueOf(x).compareTo(Integer.valueOf(y))

    Parameters:
      `x` - the first `int` to compare
      `y` - the second `int` 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(int x, int y)
    Compares two `int` values numerically treating the values as unsigned.
    Parameters:
      `x` - the first `int` to compare
      `y` - the second `int` 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:
      1.8

  - ### toUnsignedLong

    public static long toUnsignedLong(int x)
    Converts the argument to a `long` by an unsigned conversion. In an unsigned conversion to a `long`, the high-order 32 bits of the `long` are zero and the low-order 32 bits are equal to the bits of the integer argument. Consequently, zero and positive `int` values are mapped to a numerically equal `long` value and negative `int` values are mapped to a `long` value equal to the input plus 232.
    Parameters:
      `x` - the value to convert to an unsigned `long`
    Returns:
      the argument converted to `long` by an unsigned conversion
    Since:
      1.8

  - ### divideUnsigned

    public static int divideUnsigned(int dividend, int divisor)
    Returns the unsigned quotient of dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.

    Note that in two's complement arithmetic, the three other basic arithmetic operations of add, subtract, and multiply are bit-wise identical if the two operands are regarded as both being signed or both being unsigned. Therefore separate `addUnsigned`, etc. methods are not provided.

    Parameters:
      `dividend` - the value to be divided
      `divisor` - the value doing the dividing
    Returns:
      the unsigned quotient of the first argument divided by the second argument
    Since:
      1.8
    See Also:
      - `remainderUnsigned(int, int)`

  - ### remainderUnsigned

    public static int remainderUnsigned(int dividend, int divisor)
    Returns the unsigned remainder from dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
    Parameters:
      `dividend` - the value to be divided
      `divisor` - the value doing the dividing
    Returns:
      the unsigned remainder of the first argument divided by the second argument
    Since:
      1.8
    See Also:
      - `divideUnsigned(int, int)`

  - ### highestOneBit

    public static int highestOneBit(int i)
    Returns an `int` value with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specified `int` value. Returns zero if the specified value has no one-bits in its two's complement binary representation, that is, if it is equal to zero.
    Parameters:
      `i` - the value whose highest one bit is to be computed
    Returns:
      an `int` value with a single one-bit, in the position of the highest-order one-bit in the specified value, or zero if the specified value is itself equal to zero.
    Since:
      1.5

  - ### lowestOneBit

    public static int lowestOneBit(int i)
    Returns an `int` value with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specified `int` value. Returns zero if the specified value has no one-bits in its two's complement binary representation, that is, if it is equal to zero.
    Parameters:
      `i` - the value whose lowest one bit is to be computed
    Returns:
      an `int` value with a single one-bit, in the position of the lowest-order one-bit in the specified value, or zero if the specified value is itself equal to zero.
    Since:
      1.5

  - ### numberOfLeadingZeros

    public static int numberOfLeadingZeros(int i)
    Returns the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specified `int` value. Returns 32 if the specified value has no one-bits in its two's complement representation, in other words if it is equal to zero.

    Note that this method is closely related to the logarithm base 2. For all positive `int` values x:

    - floor(log2(x)) = `31 - numberOfLeadingZeros(x)`
    - ceil(log2(x)) = `32 - numberOfLeadingZeros(x - 1)`
    Parameters:
      `i` - the value whose number of leading zeros is to be computed
    Returns:
      the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specified `int` value, or 32 if the value is equal to zero.
    Since:
      1.5

  - ### numberOfTrailingZeros

    public static int numberOfTrailingZeros(int i)
    Returns the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specified `int` value. Returns 32 if the specified value has no one-bits in its two's complement representation, in other words if it is equal to zero.
    Parameters:
      `i` - the value whose number of trailing zeros is to be computed
    Returns:
      the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specified `int` value, or 32 if the value is equal to zero.
    Since:
      1.5

  - ### bitCount

    public static int bitCount(int i)
    Returns the number of one-bits in the two's complement binary representation of the specified `int` value. This function is sometimes referred to as the population count.
    Parameters:
      `i` - the value whose bits are to be counted
    Returns:
      the number of one-bits in the two's complement binary representation of the specified `int` value.
    Since:
      1.5

  - ### rotateLeft

    public static int rotateLeft(int i, int distance)
    Returns the value obtained by rotating the two's complement binary representation of the specified `int` value left by the specified number of bits. (Bits shifted out of the left hand, or high-order, side reenter on the right, or low-order.)

    Note that left rotation with a negative distance is equivalent to right rotation: `rotateLeft(val, -distance) == rotateRight(val, distance)`. Note also that rotation by any multiple of 32 is a no-op, so all but the last five bits of the rotation distance can be ignored, even if the distance is negative: `rotateLeft(val, distance) == rotateLeft(val, distance & 0x1F)`.

    Parameters:
      `i` - the value whose bits are to be rotated left
      `distance` - the number of bit positions to rotate left
    Returns:
      the value obtained by rotating the two's complement binary representation of the specified `int` value left by the specified number of bits.
    Since:
      1.5

  - ### rotateRight

    public static int rotateRight(int i, int distance)
    Returns the value obtained by rotating the two's complement binary representation of the specified `int` value right by the specified number of bits. (Bits shifted out of the right hand, or low-order, side reenter on the left, or high-order.)

    Note that right rotation with a negative distance is equivalent to left rotation: `rotateRight(val, -distance) == rotateLeft(val, distance)`. Note also that rotation by any multiple of 32 is a no-op, so all but the last five bits of the rotation distance can be ignored, even if the distance is negative: `rotateRight(val, distance) == rotateRight(val, distance & 0x1F)`.

    Parameters:
      `i` - the value whose bits are to be rotated right
      `distance` - the number of bit positions to rotate right
    Returns:
      the value obtained by rotating the two's complement binary representation of the specified `int` value right by the specified number of bits.
    Since:
      1.5

  - ### reverse

    public static int reverse(int i)
    Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified `int` value.
    Parameters:
      `i` - the value to be reversed
    Returns:
      the value obtained by reversing order of the bits in the specified `int` value.
    Since:
      1.5

  - ### compress

    public static int compress(int i, int mask)
    Returns the value obtained by compressing the bits of the specified `int` value, `i`, in accordance with the specified bit mask.

    For each one-bit value `mb` of the mask, from least significant to most significant, the bit value of `i` at the same bit location as `mb` is assigned to the compressed value contiguously starting from the least significant bit location. All the upper remaining bits of the compressed value are set to zero.

    API Note:
      Consider the simple case of compressing the digits of a hexadecimal value:

          // Compressing drink to food
          compress(0xCAFEBABE, 0xFF00FFF0) == 0xCABAB

      Starting from the least significant hexadecimal digit at position 0 from the right, the mask `0xFF00FFF0` selects hexadecimal digits at positions 1, 2, 3, 6 and 7 of `0xCAFEBABE`. The selected digits occur in the resulting compressed value contiguously from digit position 0 in the same order.

      The following identities all return `true` and are helpful to understand the behaviour of `compress`:

          // Returns 1 if the bit at position n is one
          compress(x, 1 << n) == (x >> n & 1)

          // Logical shift right
          compress(x, -1 << n) == x >>> n

          // Any bits not covered by the mask are ignored
          compress(x, m) == compress(x & m, m)

          // Compressing a value by itself
          compress(m, m) == (m == -1 || m == 0) ? m : (1 << bitCount(m)) - 1

          // Expanding then compressing with the same mask
          compress(expand(x, m), m) == x & compress(m, m)

      The Sheep And Goats (SAG) operation (see Hacker's Delight, section 7.7) can be implemented as follows:

          int compressLeft(int i, int mask) {
              // This implementation follows the description in Hacker's Delight which
              // is informative. A more optimal implementation is:
              //   Integer.compress(i, mask) << -Integer.bitCount(mask)
              return Integer.reverse(
                  Integer.compress(Integer.reverse(i), Integer.reverse(mask)));
          }

          int sag(int i, int mask) {
              return compressLeft(i, mask) | Integer.compress(i, ~mask);
          }

          // Separate the sheep from the goats
          sag(0xCAFEBABE, 0xFF00FFF0) == 0xCABABFEE

    Parameters:
      `i` - the value whose bits are to be compressed
      `mask` - the bit mask
    Returns:
      the compressed value
    Since:
      19
    See Also:
      - `expand(int, int)`

  - ### expand

    public static int expand(int i, int mask)
    Returns the value obtained by expanding the bits of the specified `int` value, `i`, in accordance with the specified bit mask.

    For each one-bit value `mb` of the mask, from least significant to most significant, the next contiguous bit value of `i` starting at the least significant bit is assigned to the expanded value at the same bit location as `mb`. All other remaining bits of the expanded value are set to zero.

    API Note:
      Consider the simple case of expanding the digits of a hexadecimal value:

          expand(0x0000CABAB, 0xFF00FFF0) == 0xCA00BAB0

      Starting from the least significant hexadecimal digit at position 0 from the right, the mask `0xFF00FFF0` selects the first five hexadecimal digits of `0x0000CABAB`. The selected digits occur in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.

      The following identities all return `true` and are helpful to understand the behaviour of `expand`:

          // Logically shift right the bit at position 0
          expand(x, 1 << n) == (x & 1) << n

          // Logically shift right
          expand(x, -1 << n) == x << n

          // Expanding all bits returns the mask
          expand(-1, m) == m

          // Any bits not covered by the mask are ignored
          expand(x, m) == expand(x, m) & m

          // Compressing then expanding with the same mask
          expand(compress(x, m), m) == x & m

      The select operation for determining the position of the one-bit with index `n` in a `int` value can be implemented as follows:

          int select(int i, int n) {
              // the one-bit in i (the mask) with index n
              int nthBit = Integer.expand(1 << n, i);
              // the bit position of the one-bit with index n
              return Integer.numberOfTrailingZeros(nthBit);
          }

          // The one-bit with index 0 is at bit position 1
          select(0b10101010_10101010, 0) == 1
          // The one-bit with index 3 is at bit position 7
          select(0b10101010_10101010, 3) == 7

    Parameters:
      `i` - the value whose bits are to be expanded
      `mask` - the bit mask
    Returns:
      the expanded value
    Since:
      19
    See Also:
      - `compress(int, int)`

  - ### signum

    public static int signum(int i)
    Returns the signum function of the specified `int` value. (The return value is -1 if the specified value is negative; 0 if the specified value is zero; and 1 if the specified value is positive.)
    Parameters:
      `i` - the value whose signum is to be computed
    Returns:
      the signum function of the specified `int` value.
    Since:
      1.5

  - ### reverseBytes

    public static int reverseBytes(int i)
    Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified `int` value.
    Parameters:
      `i` - the value whose bytes are to be reversed
    Returns:
      the value obtained by reversing the bytes in the specified `int` value.
    Since:
      1.5

  - ### sum

    public static int sum(int a, int b)
    Adds two integers together as per the + operator.
    Parameters:
      `a` - the first operand
      `b` - the second operand
    Returns:
      the sum of `a` and `b`
    Since:
      1.8
    See Also:
      - `BinaryOperator`

  - ### max

    public static int max(int a, int b)
    Returns the greater of two `int` values as if by calling `Math.max`.
    Parameters:
      `a` - the first operand
      `b` - the second operand
    Returns:
      the greater of `a` and `b`
    Since:
      1.8
    See Also:
      - `BinaryOperator`

  - ### min

    public static int min(int a, int b)
    Returns the smaller of two `int` values as if by calling `Math.min`.
    Parameters:
      `a` - the first operand
      `b` - the second operand
    Returns:
      the smaller of `a` and `b`
    Since:
      1.8
    See Also:
      - `BinaryOperator`

  - ### describeConstable

    public Optional<Integer> describeConstable()
    Returns an `Optional` containing the nominal descriptor for this instance, which is the instance itself.
    Specified by:
      `describeConstable` in interface `Constable`
    Returns:
      an `Optional` describing the Integer instance
    Since:
      12

  - ### resolveConstantDesc

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