- All Implemented Interfaces:
- Serializable,- Comparable<Integer>,- Constable,- ConstantDesc
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:
- 
Field SummaryFieldsModifier and TypeFieldDescriptionstatic final intThe number of bytes used to represent anintvalue in two's complement binary form.static final intA constant holding the maximum value anintcan have, 231-1.static final intA constant holding the minimum value anintcan have, -231.static final intThe number of bits used to represent anintvalue in two's complement binary form.TheClassinstance representing the primitive typeint.
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Constructor SummaryConstructorsConstructorDescriptionInteger(int value) Deprecated, for removal: This API element is subject to removal in a future version.It is rarely appropriate to use this constructor.Deprecated, for removal: This API element is subject to removal in a future version.It is rarely appropriate to use this constructor.
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Method SummaryModifier and TypeMethodDescriptionstatic intbitCount(int i) Returns the number of one-bits in the two's complement binary representation of the specifiedintvalue.byteReturns the value of thisIntegeras abyteafter a narrowing primitive conversion.static intcompare(int x, int y) Compares twointvalues numerically.intCompares twoIntegerobjects numerically.static intcompareUnsigned(int x, int y) Compares twointvalues numerically treating the values as unsigned.static intcompress(int i, int mask) Returns the value obtained by compressing the bits of the specifiedintvalue,i, in accordance with the specified bit mask.static IntegerDecodes aStringinto anInteger.Returns anOptionalcontaining the nominal descriptor for this instance, which is the instance itself.static intdivideUnsigned(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.doubleReturns the value of thisIntegeras adoubleafter a widening primitive conversion.booleanCompares this object to the specified object.static intexpand(int i, int mask) Returns the value obtained by expanding the bits of the specifiedintvalue,i, in accordance with the specified bit mask.floatReturns the value of thisIntegeras afloatafter a widening primitive conversion.static IntegergetInteger(String nm) Determines the integer value of the system property with the specified name.static IntegergetInteger(String nm, int val) Determines the integer value of the system property with the specified name.static IntegergetInteger(String nm, Integer val) Returns the integer value of the system property with the specified name.inthashCode()Returns a hash code for thisInteger.static inthashCode(int value) Returns a hash code for anintvalue; compatible withInteger.hashCode().static inthighestOneBit(int i) Returns anintvalue with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specifiedintvalue.intintValue()Returns the value of thisIntegeras anint.longReturns the value of thisIntegeras alongafter a widening primitive conversion.static intlowestOneBit(int i) Returns anintvalue with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specifiedintvalue.static intmax(int a, int b) Returns the greater of twointvalues as if by callingMath.max.static intmin(int a, int b) Returns the smaller of twointvalues as if by callingMath.min.static intnumberOfLeadingZeros(int i) Returns the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specifiedintvalue.static intnumberOfTrailingZeros(int i) Returns the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specifiedintvalue.static intparseInt(CharSequence s, int beginIndex, int endIndex, int radix) Parses theCharSequenceargument as a signedintin the specifiedradix, beginning at the specifiedbeginIndexand extending toendIndex - 1.static intParses the string argument as a signed decimal integer.static intParses the string argument as a signed integer in the radix specified by the second argument.static intparseUnsignedInt(CharSequence s, int beginIndex, int endIndex, int radix) Parses theCharSequenceargument as an unsignedintin the specifiedradix, beginning at the specifiedbeginIndexand extending toendIndex - 1.static intParses the string argument as an unsigned decimal integer.static intparseUnsignedInt(String s, int radix) Parses the string argument as an unsigned integer in the radix specified by the second argument.static intremainderUnsigned(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.Resolves this instance as aConstantDesc, the result of which is the instance itself.static intreverse(int i) Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specifiedintvalue.static intreverseBytes(int i) Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specifiedintvalue.static introtateLeft(int i, int distance) Returns the value obtained by rotating the two's complement binary representation of the specifiedintvalue left by the specified number of bits.static introtateRight(int i, int distance) Returns the value obtained by rotating the two's complement binary representation of the specifiedintvalue right by the specified number of bits.shortReturns the value of thisIntegeras ashortafter a narrowing primitive conversion.static intsignum(int i) Returns the signum function of the specifiedintvalue.static intsum(int a, int b) Adds two integers together as per the + operator.static StringtoBinaryString(int i) Returns a string representation of the integer argument as an unsigned integer in base 2.static StringtoHexString(int i) Returns a string representation of the integer argument as an unsigned integer in base 16.static StringtoOctalString(int i) Returns a string representation of the integer argument as an unsigned integer in base 8.toString()Returns aStringobject representing thisInteger's value.static StringtoString(int i) Returns aStringobject representing the specified integer.static StringtoString(int i, int radix) Returns a string representation of the first argument in the radix specified by the second argument.static longtoUnsignedLong(int x) Converts the argument to alongby an unsigned conversion.static StringtoUnsignedString(int i) Returns a string representation of the argument as an unsigned decimal value.static StringtoUnsignedString(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 IntegervalueOf(int i) Returns anIntegerinstance representing the specifiedintvalue.static IntegerReturns anIntegerobject holding the value of the specifiedString.static IntegerReturns anIntegerobject holding the value extracted from the specifiedStringwhen parsed with the radix given by the second argument.
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Field Details- 
MIN_VALUEA constant holding the minimum value anintcan have, -231.- See Also:
 
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MAX_VALUEA constant holding the maximum value anintcan have, 231-1.- See Also:
 
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TYPETheClassinstance representing the primitive typeint.- Since:
- 1.1
 
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SIZEThe number of bits used to represent anintvalue in two's complement binary form.- Since:
- 1.5
- See Also:
 
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BYTESpublic static final int BYTESThe number of bytes used to represent anintvalue in two's complement binary form.- Since:
- 1.8
- See Also:
 
 
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- 
Constructor Details- 
IntegerDeprecated, for removal: This API element is subject to removal in a future version.It is rarely appropriate to use this constructor. The static factoryvalueOf(int)is generally a better choice, as it is likely to yield significantly better space and time performance.Constructs a newly allocatedIntegerobject that represents the specifiedintvalue.- Parameters:
- value- the value to be represented by the- Integerobject.
 
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IntegerDeprecated, for removal: This API element is subject to removal in a future version.It is rarely appropriate to use this constructor. UseparseInt(String)to convert a string to aintprimitive, or usevalueOf(String)to convert a string to anIntegerobject.Constructs a newly allocatedIntegerobject that represents theintvalue indicated by theStringparameter. The string is converted to anintvalue in exactly the manner used by theparseIntmethod for radix 10.- Parameters:
- s- the- Stringto be converted to an- Integer.
- Throws:
- NumberFormatException- if the- Stringdoes not contain a parsable integer.
 
 
- 
- 
Method Details- 
toStringReturns a string representation of the first argument in the radix specified by the second argument.If the radix is smaller than Character.MIN_RADIXor larger thanCharacter.MAX_RADIX, then the radix10is 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:
 These are0123456789abcdefghijklmnopqrstuvwxyz'\u0030'through'\u0039'and'\u0061'through'\u007A'. Ifradixis 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) are0123456789abcdef. If uppercase letters are desired, theString.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:
 
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toUnsignedStringReturns 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_RADIXor larger thanCharacter.MAX_RADIX, then the radix10is 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:
 
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toHexStringReturns 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 sby callingInteger.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:
 These are the characters0123456789abcdef'\u0030'through'\u0039'and'\u0061'through'\u0066'. If uppercase letters are desired, theString.toUpperCase()method may be called on the result:Integer.toHexString(n).toUpperCase()- API Note:
- The HexFormatclass provides formatting and parsing of byte arrays and primitives to return a string or adding to anAppendable.HexFormatformats 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:
 
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toOctalStringReturns 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 sby callingInteger.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:
 These are the characters01234567'\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:
 
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toBinaryStringReturns 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 sby callingInteger.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:
 
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toStringReturns aStringobject 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 thetoString(int, int)method.- Parameters:
- i- an integer to be converted.
- Returns:
- a string representation of the argument in base 10.
 
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toUnsignedStringReturns 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 thetoUnsignedString(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:
 
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parseIntParses 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 whetherCharacter.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 NumberFormatExceptionis thrown if any of the following situations occurs:- The first argument is nullor is a string of length zero.
- The radix is either smaller than
 Character.MIN_RADIXor larger thanCharacter.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- Stringcontaining 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- Stringdoes not contain a parsable- int.
 
- The first argument is 
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parseIntpublic static int parseInt(CharSequence s, int beginIndex, int endIndex, int radix) throws NumberFormatException Parses theCharSequenceargument as a signedintin the specifiedradix, beginning at the specifiedbeginIndexand extending toendIndex - 1.The method does not take steps to guard against the CharSequencebeing mutated while parsing.- Parameters:
- s- the- CharSequencecontaining the- intrepresentation 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 intrepresented by the subsequence in the specified radix.
- Throws:
- NullPointerException- if- sis null.
- IndexOutOfBoundsException- if- beginIndexis negative, or if- beginIndexis greater than- endIndexor if- endIndexis greater than- s.length().
- NumberFormatException- if the- CharSequencedoes not contain a parsable- intin the specified- radix, or if- radixis either smaller than- Character.MIN_RADIXor larger than- Character.MAX_RADIX.
- Since:
- 9
 
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parseIntParses 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 theparseInt(java.lang.String, int)method.- Parameters:
- s- a- Stringcontaining the- intrepresentation to be parsed
- Returns:
- the integer value represented by the argument in decimal.
- Throws:
- NumberFormatException- if the string does not contain a parsable integer.
 
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parseUnsignedIntParses 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 thanMAX_VALUE. The characters in the string must all be digits of the specified radix (as determined by whetherCharacter.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 NumberFormatExceptionis thrown if any of the following situations occurs:- The first argument is nullor is a string of length zero.
- The radix is either smaller than
 Character.MIN_RADIXor larger thanCharacter.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- Stringcontaining 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- Stringdoes not contain a parsable- int.
- Since:
- 1.8
 
- The first argument is 
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parseUnsignedIntpublic static int parseUnsignedInt(CharSequence s, int beginIndex, int endIndex, int radix) throws NumberFormatException Parses theCharSequenceargument as an unsignedintin the specifiedradix, beginning at the specifiedbeginIndexand extending toendIndex - 1.The method does not take steps to guard against the CharSequencebeing mutated while parsing.- Parameters:
- s- the- CharSequencecontaining the unsigned- intrepresentation 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 intrepresented by the subsequence in the specified radix.
- Throws:
- NullPointerException- if- sis null.
- IndexOutOfBoundsException- if- beginIndexis negative, or if- beginIndexis greater than- endIndexor if- endIndexis greater than- s.length().
- NumberFormatException- if the- CharSequencedoes not contain a parsable unsigned- intin the specified- radix, or if- radixis either smaller than- Character.MIN_RADIXor larger than- Character.MAX_RADIX.
- Since:
- 9
 
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parseUnsignedIntParses 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 theparseUnsignedInt(java.lang.String, int)method.- Parameters:
- s- a- Stringcontaining the unsigned- intrepresentation 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
 
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valueOfReturns anIntegerobject holding the value extracted from the specifiedStringwhen 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 theparseInt(java.lang.String, int)method. The result is anIntegerobject that represents the integer value specified by the string.In other words, this method returns an Integerobject 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 Integerobject holding the value represented by the string argument in the specified radix.
- Throws:
- NumberFormatException- if the- Stringdoes not contain a parsable- int.
 
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valueOfReturns anIntegerobject holding the value of the specifiedString. The argument is interpreted as representing a signed decimal integer, exactly as if the argument were given to theparseInt(java.lang.String)method. The result is anIntegerobject that represents the integer value specified by the string.In other words, this method returns an Integerobject equal to the value of:Integer.valueOf(Integer.parseInt(s))- Parameters:
- s- the string to be parsed.
- Returns:
- an Integerobject holding the value represented by the string argument.
- Throws:
- NumberFormatException- if the string cannot be parsed as an integer.
 
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valueOfReturns anIntegerinstance representing the specifiedintvalue. If a newIntegerinstance is not required, this method should generally be used in preference to the constructorInteger(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- intvalue.
- Returns:
- an Integerinstance representingi.
- Since:
- 1.5
 
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byteValuepublic byte byteValue()Returns the value of thisIntegeras abyteafter a narrowing primitive conversion.- Overrides:
- byteValuein 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
 
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shortValuepublic short shortValue()Returns the value of thisIntegeras ashortafter a narrowing primitive conversion.- Overrides:
- shortValuein 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
 
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intValuepublic int intValue()Returns the value of thisIntegeras anint.
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longValuepublic long longValue()Returns the value of thisIntegeras alongafter a widening primitive conversion.- Specified by:
- longValuein class- Number
- Returns:
- the numeric value represented by this object after conversion
          to type long.
- See Java Language Specification:
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5.1.2 Widening Primitive Conversion
- See Also:
 
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floatValuepublic float floatValue()Returns the value of thisIntegeras afloatafter a widening primitive conversion.- Specified by:
- floatValuein 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
 
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doubleValuepublic double doubleValue()Returns the value of thisIntegeras adoubleafter a widening primitive conversion.- Specified by:
- doubleValuein 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
 
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toStringReturns aStringobject representing thisInteger'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 thetoString(int)method.
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hashCodepublic int hashCode()Returns a hash code for thisInteger.
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hashCodepublic static int hashCode(int value) Returns a hash code for anintvalue; compatible withInteger.hashCode().- Parameters:
- value- the value to hash
- Returns:
- a hash code value for an intvalue.
- Since:
- 1.8
 
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equalsCompares this object to the specified object. The result istrueif and only if the argument is notnulland is anIntegerobject that contains the sameintvalue as this object.
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getIntegerDetermines 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 bydecodeand anIntegerobject 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, thennullis returned.In other words, this method returns an Integerobject equal to the value of:getInteger(nm, null)- Parameters:
- nm- property name.
- Returns:
- the Integervalue of the property.
- Throws:
- SecurityException- for the same reasons as- System.getProperty
- See Also:
 
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getIntegerDetermines 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 bydecodeand anIntegerobject representing this value is returned.The second argument is the default value. An Integerobject 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 ornull.In other words, this method returns an Integerobject equal to the value of:
 but in practice it may be implemented in a manner such as:getInteger(nm, Integer.valueOf(val))
 to avoid the unnecessary allocation of anInteger result = getInteger(nm, null); return (result == null) ? Integer.valueOf(val) : result; Integerobject when the default value is not needed.- Parameters:
- nm- property name.
- val- default value.
- Returns:
- the Integervalue of the property.
- Throws:
- SecurityException- for the same reasons as- System.getProperty
- See Also:
 
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getIntegerReturns 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 theSystem.getProperty(java.lang.String)method. The string value of this property is then interpreted as an integer value, as per thedecodemethod, and anIntegerobject representing this value is returned; in summary:- If the property value begins with the two ASCII characters
         0xor the ASCII character#, not followed by a minus sign, then the rest of it is parsed as a hexadecimal integer exactly as by the methodvalueOf(java.lang.String, int)with radix 16.
- If the property value begins with the ASCII character
     0followed by another character, it is parsed as an octal integer exactly as by the methodvalueOf(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 Integervalue of the property.
- Throws:
- SecurityException- for the same reasons as- System.getProperty
- See Also:
 
- If the property value begins with the two ASCII characters
         
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decodeDecodes aStringinto anInteger. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:
 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.- DecodableString:
- Signopt DecimalNumeral
 - Signopt
0xHexDigits
- Signopt
0XHexDigits
- Signopt
#HexDigits
- Signopt
0OctalDigits
- Signopt
- Sign:
- -- +
 The sequence of characters following an optional sign and/or radix specifier (" 0x", "0X", "#", or leading zero) is parsed as by theInteger.parseIntmethod with the indicated radix (10, 16, or 8). This sequence of characters must represent a positive value or aNumberFormatExceptionwill be thrown. The result is negated if first character of the specifiedStringis the minus sign. No whitespace characters are permitted in theString.- Parameters:
- nm- the- Stringto decode.
- Returns:
- an Integerobject holding theintvalue represented bynm
- Throws:
- NumberFormatException- if the- Stringdoes not contain a parsable integer.
- See Also:
 
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compareToCompares twoIntegerobjects numerically.- Specified by:
- compareToin interface- Comparable<Integer>
- Parameters:
- anotherInteger- the- Integerto be compared.
- Returns:
- the value 0if thisIntegeris equal to the argumentInteger; a value less than0if thisIntegeris numerically less than the argumentInteger; and a value greater than0if thisIntegeris numerically greater than the argumentInteger(signed comparison).
- Since:
- 1.2
 
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comparepublic static int compare(int x, int y) Compares twointvalues numerically. The value returned is identical to what would be returned by:Integer.valueOf(x).compareTo(Integer.valueOf(y))- Parameters:
- x- the first- intto compare
- y- the second- intto compare
- Returns:
- the value 0ifx == y; a value less than0ifx < y; and a value greater than0ifx > y
- Since:
- 1.7
 
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compareUnsignedpublic static int compareUnsigned(int x, int y) Compares twointvalues numerically treating the values as unsigned.- Parameters:
- x- the first- intto compare
- y- the second- intto compare
- Returns:
- the value 0ifx == y; a value less than0ifx < yas unsigned values; and a value greater than0ifx > yas unsigned values
- Since:
- 1.8
 
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toUnsignedLongpublic static long toUnsignedLong(int x) Converts the argument to alongby an unsigned conversion. In an unsigned conversion to along, the high-order 32 bits of thelongare zero and the low-order 32 bits are equal to the bits of the integer argument. Consequently, zero and positiveintvalues are mapped to a numerically equallongvalue and negativeintvalues are mapped to alongvalue equal to the input plus 232.- Parameters:
- x- the value to convert to an unsigned- long
- Returns:
- the argument converted to longby an unsigned conversion
- Since:
- 1.8
 
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divideUnsignedpublic 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:
 
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remainderUnsignedpublic 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:
 
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highestOneBitpublic static int highestOneBit(int i) Returns anintvalue with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specifiedintvalue. 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 intvalue 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
 
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lowestOneBitpublic static int lowestOneBit(int i) Returns anintvalue with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specifiedintvalue. 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 intvalue 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
 
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numberOfLeadingZerospublic 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 specifiedintvalue. 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 intvalues 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 intvalue, or 32 if the value is equal to zero.
- Since:
- 1.5
 
- floor(log2(x)) = 
- 
numberOfTrailingZerospublic 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 specifiedintvalue. 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 intvalue, or 32 if the value is equal to zero.
- Since:
- 1.5
 
- 
bitCountpublic static int bitCount(int i) Returns the number of one-bits in the two's complement binary representation of the specifiedintvalue. 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 intvalue.
- Since:
- 1.5
 
- 
rotateLeftpublic static int rotateLeft(int i, int distance) Returns the value obtained by rotating the two's complement binary representation of the specifiedintvalue 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 intvalue left by the specified number of bits.
- Since:
- 1.5
 
- 
rotateRightpublic static int rotateRight(int i, int distance) Returns the value obtained by rotating the two's complement binary representation of the specifiedintvalue 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 intvalue right by the specified number of bits.
- Since:
- 1.5
 
- 
reversepublic 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 specifiedintvalue.- Parameters:
- i- the value to be reversed
- Returns:
- the value obtained by reversing order of the bits in the
     specified intvalue.
- Since:
- 1.5
 
- 
compresspublic static int compress(int i, int mask) Returns the value obtained by compressing the bits of the specifiedintvalue,i, in accordance with the specified bit mask.For each one-bit value mbof the mask, from least significant to most significant, the bit value ofiat the same bit location asmbis 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:
 
Starting from the least significant hexadecimal digit at position 0 from the right, the mask// Compressing drink to food compress(0xCAFEBABE, 0xFF00FFF0) == 0xCABAB0xFF00FFF0selects hexadecimal digits at positions 1, 2, 3, 6 and 7 of0xCAFEBABE. The selected digits occur in the resulting compressed value contiguously from digit position 0 in the same order.The following identities all return trueand are helpful to understand the behaviour ofcompress:// 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:
 
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expandpublic static int expand(int i, int mask) Returns the value obtained by expanding the bits of the specifiedintvalue,i, in accordance with the specified bit mask.For each one-bit value mbof the mask, from least significant to most significant, the next contiguous bit value ofistarting at the least significant bit is assigned to the expanded value at the same bit location asmb. 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:
 
Starting from the least significant hexadecimal digit at position 0 from the right, the maskexpand(0x0000CABAB, 0xFF00FFF0) == 0xCA00BAB00xFF00FFF0selects the first five hexadecimal digits of0x0000CABAB. The selected digits occur in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.The following identities all return trueand are helpful to understand the behaviour ofexpand:// 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 & mThe select operation for determining the position of the one-bit with index nin aintvalue 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:
 
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signumpublic static int signum(int i) Returns the signum function of the specifiedintvalue. (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 intvalue.
- Since:
- 1.5
 
- 
reverseBytespublic static int reverseBytes(int i) Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specifiedintvalue.- Parameters:
- i- the value whose bytes are to be reversed
- Returns:
- the value obtained by reversing the bytes in the specified
     intvalue.
- Since:
- 1.5
 
- 
sumpublic 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 aandb
- Since:
- 1.8
- See Also:
 
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maxpublic static int max(int a, int b) Returns the greater of twointvalues as if by callingMath.max.- Parameters:
- a- the first operand
- b- the second operand
- Returns:
- the greater of aandb
- Since:
- 1.8
- See Also:
 
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minpublic static int min(int a, int b) Returns the smaller of twointvalues as if by callingMath.min.- Parameters:
- a- the first operand
- b- the second operand
- Returns:
- the smaller of aandb
- Since:
- 1.8
- See Also:
 
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describeConstableReturns anOptionalcontaining the nominal descriptor for this instance, which is the instance itself.- Specified by:
- describeConstablein interface- Constable
- Returns:
- an Optionaldescribing the Integer instance
- Since:
- 12
 
- 
resolveConstantDescResolves this instance as aConstantDesc, the result of which is the instance itself.- Specified by:
- resolveConstantDescin interface- ConstantDesc
- Parameters:
- lookup- ignored
- Returns:
- the Integer instance
- Since:
- 12
 
 
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