Java compact1, compact2, compact3 java.lang Class Integer（JDK8）

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Java™ Platform
Standard Ed. 8

All Classes

Summary:
Nested |
Field |
Constr |
Method

Detail:
Field |
Constr |
Method

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

All Implemented Interfaces:

Serializable, Comparable<Integer>
```
public final class Integer
extends Number
implements Comparable<Integer>
```
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.

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:

JDK1.0

See Also:

Serialized Form

Field Summary

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

Constructor Summary

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

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and 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 Integer`	`decode(String nm)` Decodes a `String` into an `Integer`.
`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.
`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 a `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(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(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.
`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 inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - 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:
    
    JDK1.1
  - 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 a int value in two's complement binary form.
    
    Since:
    
    1.8
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Integer
```
public Integer(int value)
```
    Constructs a newly allocated Integer object that represents the specified int value.
    
    Parameters:
    
    value - the value to be represented by the Integer object.
  - Integer
```
public Integer(String s)
        throws NumberFormatException
```
    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.
    
    See Also:
    
    parseInt(java.lang.String, int)
- Method Detail
  - 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 0s.
    
    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()
    
    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:
    
    JDK1.0.2
    
    See Also:
    
    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 0s.
    
    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:
    
    JDK1.0.2
    
    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 0s.
    
    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:
    
    JDK1.0.2
    
    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(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(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 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:
    
    new Integer(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:
    
    new Integer(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 The Java™ Language Specification:
    
    5.1.3 Narrowing Primitive Conversions
  - 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 The Java™ Language Specification:
    
    5.1.3 Narrowing Primitive Conversions
  - 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 Also:
    
    toUnsignedLong(int)
    
    See The Java™ Language Specification:
    
    5.1.2 Widening Primitive Conversions
  - 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 The Java™ Language Specification:
    
    5.1.2 Widening Primitive Conversions
  - 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 The Java™ Language Specification:
    
    5.1.2 Widening Primitive Conversions
  - 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 a int value; compatible with Integer.hashCode().
    
    Parameters:
    
    value - the value to hash
    
    Returns:
    
    a hash code value for a 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, new Integer(val))
    but in practice it may be implemented in a manner such as:
    Integer result = getInteger(nm, null); return (result == null) ? new Integer(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:
    
    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 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
  - 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

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Java compact1, compact2, compact3 java.lang Class Integer（JDK8）

Class Integer

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MIN_VALUE

MAX_VALUE

TYPE

SIZE

BYTES

Constructor Detail

Integer

Integer

Method Detail

toString

toUnsignedString

toHexString

toOctalString

toBinaryString

toString

toUnsignedString

parseInt

parseInt

parseUnsignedInt

parseUnsignedInt

valueOf

valueOf

valueOf

byteValue

shortValue

intValue

longValue

floatValue

doubleValue

toString

hashCode

hashCode

equals

getInteger

getInteger

getInteger

decode

compareTo

compare

compareUnsigned

toUnsignedLong

divideUnsigned

remainderUnsigned

highestOneBit

lowestOneBit

numberOfLeadingZeros

numberOfTrailingZeros

bitCount

rotateLeft

rotateRight

reverse

signum

reverseBytes

sum

max

min