An explanation and purpose of the integer class in Java

Java.lang
Class Integer

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 the value of a primitive type int in the object. An object of type Integer contains a field of type int.

In addition, the class provides several methods for converting between int and String types, as well as some other constants and methods that are useful when working with int types.

Implementation considerations: The implementation of the "bit twiddling" method (such as Highestonebit and Numberoftrailingzeros) is based on Henry S. Warren, Hacker's Delight, written by Jr. (Addison Wesley, 2002) in some of the relevant materials.

start from the following versions:

JDK1.0

See also:

Serialization table

Field Summary
static int	Max_value The constant that holds the maximum value of type int is the desirable value of 231-1.
static int	Min_value The constant that holds the minimum value of type int is the desirable value of-231.
static int	SIZE Represents the number of digits of an int value in twos complement form.
Static class<integer>	TYPE Represents a Class instance of the base type int.

Construction Method Summary
Integer (int value) Constructs a newly assigned Integer object that represents the specified int value.
Integer (String s) Constructs a newly assigned Integer object that represents the int value indicated by the String parameter.

Method Summary
static int	Bitcount (int i) Returns the number of 1 bits in the binary complement representation of the specified int value.
Byte	Bytevalue () Returns the value of the Integer in byte type.
Int	CompareTo (Integer Anotherinteger) Compares two Integer objects on a number.
Static Integer	Decode (String nm) Decodes a String to an Integer.
Double	Doublevalue () Returns the value of this Integer as a double type.
Boolean	equals (Object obj) Compares this object with the specified object.
Float	Floatvalue () Returns the value of this Integer as a float type.
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 the hash code for this Integer.
static int	Highestonebit (int i) Returns the position of the highest (leftmost) 1 bits of an int value with a maximum of 1 bits in the specified int value.
Int	Intvalue () Returns the value of the Integer as the int type.
Long	Longvalue () Returns the value of this Integer as a long type.
static int	Lowestonebit (int i) Returns the position of an int value with a maximum of 1 bits, the lowest bit in the specified int value (rightmost), and 1 bits.
static int	Numberofleadingzeros (int i) Returns the number of 0 bits before specifying the 1 bits of the highest bit (leftmost) in the binary complement representation of an int value.
static int	Numberoftrailingzeros (int i) Returns the number of 0 digits following the lowest ("right-most") digit in the binary complement representation of the specified int value, which is 1.
static int	parseint (String s) The string argument is parsed as a signed decimal integer.
static int	parseint (String s, int radix) Resolves a string argument to a signed integer using the cardinality specified by the second argument.
static int	Reverse (int i) Returns the value obtained by reversing the order of the bits in the binary complement representation of the specified int value.
static int	reversebytes (int i) Returns the value obtained by reversing the order of the bytes in the binary complement representation of the specified int value.
static int	Rotateleft (int i, int distance) Returns the value obtained from the binary complement representation of the specified int value, based on the specified number of digits in the loop.
static int	Rotateright (int i, int distance) Returns the value that is obtained from the binary complement representation of the specified int value, based on the specified number of bits looping right.
Short	Shortvalue () Returns the value of the Integer in the short type.
static int	Signum (int i) Returns a symbolic function that specifies an int value.
Static String	tobinarystring (int i) Returns a string representation of an integer parameter as a binary (radix 2) unsigned integer.
Static String	tohexstring (int i) Returns a string representation of an integer parameter as an unsigned 16-based integer.
Static String	tooctalstring (int i) Returns a string representation of an integer parameter as a eight-based (radix 8) unsigned integer.
String	toString () Returns a String object that represents the Integer value.
Static String	toString (int i) Returns a String object that represents the specified integer.
Static String	toString (int i, int radix) Returns the string representation of the first argument, using the cardinality specified by the second argument.
Static Integer	valueOf (int i) Returns an Integer instance that represents the specified int value.
Static Integer	valueOf (String s) Returns an Integer object that holds the value of the specified String.
Static Integer	valueOf (String s, int radix) Returns an Integer object that retains the value extracted from the specified String when parsed with the cardinality provided by the second argument.

An explanation and purpose of the integer class in Java