Module java.base
Package java.lang

Class Character

java.lang.Object
java.lang.Character
All Implemented Interfaces:
Serializable, Comparable<Character>, Constable
public final class Character extends Object implements Serializable, Comparable<Character>, Constable
The Character class wraps a value of the primitive type char in an object. An object of class Character contains a single field whose type is char.

In addition, this class provides a large number of static methods for determining a character's category (lowercase letter, digit, etc.) and for converting characters from uppercase to lowercase and vice versa.

Unicode Conformance

The fields and methods of class Character are defined in terms of character information from the Unicode Standard, specifically the UnicodeData file that is part of the Unicode Character Database. This file specifies properties including name and category for every assigned Unicode code point or character range. The file is available from the Unicode Consortium at http://www.unicode.org.

Character information is based on the Unicode Standard, version 13.0.

The Java platform has supported different versions of the Unicode Standard over time. Upgrades to newer versions of the Unicode Standard occurred in the following Java releases, each indicating the new version:

Shows Java releases and supported Unicode versions
Java release Unicode version
Java SE 15 Unicode 13.0
Java SE 13 Unicode 12.1
Java SE 12 Unicode 11.0
Java SE 11 Unicode 10.0
Java SE 9 Unicode 8.0
Java SE 8 Unicode 6.2
Java SE 7 Unicode 6.0
Java SE 5.0 Unicode 4.0
Java SE 1.4 Unicode 3.0
JDK 1.1 Unicode 2.0
JDK 1.0.2 Unicode 1.1.5
Variations from these base Unicode versions, such as recognized appendixes, are documented elsewhere.

Unicode Character Representations

The char data type (and therefore the value that a Character object encapsulates) are based on the original Unicode specification, which defined characters as fixed-width 16-bit entities. The Unicode Standard has since been changed to allow for characters whose representation requires more than 16 bits. The range of legal code points is now U+0000 to U+10FFFF, known as Unicode scalar value. (Refer to the definition of the U+n notation in the Unicode Standard.)

The set of characters from U+0000 to U+FFFF is sometimes referred to as the Basic Multilingual Plane (BMP). Characters whose code points are greater than U+FFFF are called supplementary characters. The Java platform uses the UTF-16 representation in char arrays and in the String and StringBuffer classes. In this representation, supplementary characters are represented as a pair of char values, the first from the high-surrogates range, (\uD800-\uDBFF), the second from the low-surrogates range (\uDC00-\uDFFF).

A char value, therefore, represents Basic Multilingual Plane (BMP) code points, including the surrogate code points, or code units of the UTF-16 encoding. An int value represents all Unicode code points, including supplementary code points. The lower (least significant) 21 bits of int are used to represent Unicode code points and the upper (most significant) 11 bits must be zero. Unless otherwise specified, the behavior with respect to supplementary characters and surrogate char values is as follows:

  • The methods that only accept a char value cannot support supplementary characters. They treat char values from the surrogate ranges as undefined characters. For example, Character.isLetter('\uD840') returns false, even though this specific value if followed by any low-surrogate value in a string would represent a letter.
  • The methods that accept an int value support all Unicode characters, including supplementary characters. For example, Character.isLetter(0x2F81A) returns true because the code point value represents a letter (a CJK ideograph).

In the Java SE API documentation, Unicode code point is used for character values in the range between U+0000 and U+10FFFF, and Unicode code unit is used for 16-bit char values that are code units of the UTF-16 encoding. For more information on Unicode terminology, refer to the Unicode Glossary.

This is a value-based class; programmers should treat instances that are equal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail.

Since:
1.0
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    Character.Subset
    Instances of this class represent particular subsets of the Unicode character set.
    static final class 
    Character.UnicodeBlock
    A family of character subsets representing the character blocks in the Unicode specification.
    static enum 
    Character.UnicodeScript
    A family of character subsets representing the character scripts defined in the Unicode Standard Annex #24: Script Names.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    BYTES
    The number of bytes used to represent a char value in unsigned binary form.
    static final byte
    COMBINING_SPACING_MARK
    General category "Mc" in the Unicode specification.
    static final byte
    CONNECTOR_PUNCTUATION
    General category "Pc" in the Unicode specification.
    static final byte
    CONTROL
    General category "Cc" in the Unicode specification.
    static final byte
    CURRENCY_SYMBOL
    General category "Sc" in the Unicode specification.
    static final byte
    DASH_PUNCTUATION
    General category "Pd" in the Unicode specification.
    static final byte
    DECIMAL_DIGIT_NUMBER
    General category "Nd" in the Unicode specification.
    static final byte
    DIRECTIONALITY_ARABIC_NUMBER
    Weak bidirectional character type "AN" in the Unicode specification.
    static final byte
    DIRECTIONALITY_BOUNDARY_NEUTRAL
    Weak bidirectional character type "BN" in the Unicode specification.
    static final byte
    DIRECTIONALITY_COMMON_NUMBER_SEPARATOR
    Weak bidirectional character type "CS" in the Unicode specification.
    static final byte
    DIRECTIONALITY_EUROPEAN_NUMBER
    Weak bidirectional character type "EN" in the Unicode specification.
    static final byte
    DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR
    Weak bidirectional character type "ES" in the Unicode specification.
    static final byte
    DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR
    Weak bidirectional character type "ET" in the Unicode specification.
    static final byte
    DIRECTIONALITY_FIRST_STRONG_ISOLATE
    Weak bidirectional character type "FSI" in the Unicode specification.
    static final byte
    DIRECTIONALITY_LEFT_TO_RIGHT
    Strong bidirectional character type "L" in the Unicode specification.
    static final byte
    DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING
    Strong bidirectional character type "LRE" in the Unicode specification.
    static final byte
    DIRECTIONALITY_LEFT_TO_RIGHT_ISOLATE
    Weak bidirectional character type "LRI" in the Unicode specification.
    static final byte
    DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE
    Strong bidirectional character type "LRO" in the Unicode specification.
    static final byte
    DIRECTIONALITY_NONSPACING_MARK
    Weak bidirectional character type "NSM" in the Unicode specification.
    static final byte
    DIRECTIONALITY_OTHER_NEUTRALS
    Neutral bidirectional character type "ON" in the Unicode specification.
    static final byte
    DIRECTIONALITY_PARAGRAPH_SEPARATOR
    Neutral bidirectional character type "B" in the Unicode specification.
    static final byte
    DIRECTIONALITY_POP_DIRECTIONAL_FORMAT
    Weak bidirectional character type "PDF" in the Unicode specification.
    static final byte
    DIRECTIONALITY_POP_DIRECTIONAL_ISOLATE
    Weak bidirectional character type "PDI" in the Unicode specification.
    static final byte
    DIRECTIONALITY_RIGHT_TO_LEFT
    Strong bidirectional character type "R" in the Unicode specification.
    static final byte
    DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC
    Strong bidirectional character type "AL" in the Unicode specification.
    static final byte
    DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING
    Strong bidirectional character type "RLE" in the Unicode specification.
    static final byte
    DIRECTIONALITY_RIGHT_TO_LEFT_ISOLATE
    Weak bidirectional character type "RLI" in the Unicode specification.
    static final byte
    DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE
    Strong bidirectional character type "RLO" in the Unicode specification.
    static final byte
    DIRECTIONALITY_SEGMENT_SEPARATOR
    Neutral bidirectional character type "S" in the Unicode specification.
    static final byte
    DIRECTIONALITY_UNDEFINED
    Undefined bidirectional character type.
    static final byte
    DIRECTIONALITY_WHITESPACE
    Neutral bidirectional character type "WS" in the Unicode specification.
    static final byte
    ENCLOSING_MARK
    General category "Me" in the Unicode specification.
    static final byte
    END_PUNCTUATION
    General category "Pe" in the Unicode specification.
    static final byte
    FINAL_QUOTE_PUNCTUATION
    General category "Pf" in the Unicode specification.
    static final byte
    FORMAT
    General category "Cf" in the Unicode specification.
    static final byte
    INITIAL_QUOTE_PUNCTUATION
    General category "Pi" in the Unicode specification.
    static final byte
    LETTER_NUMBER
    General category "Nl" in the Unicode specification.
    static final byte
    LINE_SEPARATOR
    General category "Zl" in the Unicode specification.
    static final byte
    LOWERCASE_LETTER
    General category "Ll" in the Unicode specification.
    static final byte
    MATH_SYMBOL
    General category "Sm" in the Unicode specification.
    static final int
    MAX_CODE_POINT
    The maximum value of a Unicode code point, constant U+10FFFF.
    static final char
    MAX_HIGH_SURROGATE
    The maximum value of a Unicode high-surrogate code unit in the UTF-16 encoding, constant '\uDBFF'.
    static final char
    MAX_LOW_SURROGATE
    The maximum value of a Unicode low-surrogate code unit in the UTF-16 encoding, constant '\uDFFF'.
    static final int
    MAX_RADIX
    The maximum radix available for conversion to and from strings.
    static final char
    MAX_SURROGATE
    The maximum value of a Unicode surrogate code unit in the UTF-16 encoding, constant '\uDFFF'.
    static final char
    MAX_VALUE
    The constant value of this field is the largest value of type char, '\uFFFF'.
    static final int
    MIN_CODE_POINT
    The minimum value of a Unicode code point, constant U+0000.
    static final char
    MIN_HIGH_SURROGATE
    The minimum value of a Unicode high-surrogate code unit in the UTF-16 encoding, constant '\uD800'.
    static final char
    MIN_LOW_SURROGATE
    The minimum value of a Unicode low-surrogate code unit in the UTF-16 encoding, constant '\uDC00'.
    static final int
    MIN_RADIX
    The minimum radix available for conversion to and from strings.
    static final int
    MIN_SUPPLEMENTARY_CODE_POINT
    The minimum value of a Unicode supplementary code point, constant U+10000.
    static final char
    MIN_SURROGATE
    The minimum value of a Unicode surrogate code unit in the UTF-16 encoding, constant '\uD800'.
    static final char
    MIN_VALUE
    The constant value of this field is the smallest value of type char, '\u0000'.
    static final byte
    MODIFIER_LETTER
    General category "Lm" in the Unicode specification.
    static final byte
    MODIFIER_SYMBOL
    General category "Sk" in the Unicode specification.
    static final byte
    NON_SPACING_MARK
    General category "Mn" in the Unicode specification.
    static final byte
    OTHER_LETTER
    General category "Lo" in the Unicode specification.
    static final byte
    OTHER_NUMBER
    General category "No" in the Unicode specification.
    static final byte
    OTHER_PUNCTUATION
    General category "Po" in the Unicode specification.
    static final byte
    OTHER_SYMBOL
    General category "So" in the Unicode specification.
    static final byte
    PARAGRAPH_SEPARATOR
    General category "Zp" in the Unicode specification.
    static final byte
    PRIVATE_USE
    General category "Co" in the Unicode specification.
    static final int
    SIZE
    The number of bits used to represent a char value in unsigned binary form, constant 16.
    static final byte
    SPACE_SEPARATOR
    General category "Zs" in the Unicode specification.
    static final byte
    START_PUNCTUATION
    General category "Ps" in the Unicode specification.
    static final byte
    SURROGATE
    General category "Cs" in the Unicode specification.
    static final byte
    TITLECASE_LETTER
    General category "Lt" in the Unicode specification.
    static final Class<Character>
    TYPE
    The Class instance representing the primitive type char.
    static final byte
    UNASSIGNED
    General category "Cn" in the Unicode specification.
    static final byte
    UPPERCASE_LETTER
    General category "Lu" in the Unicode specification.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Character(char value)
    Deprecated, for removal: This API element is subject to removal in a future version.
    It is rarely appropriate to use this constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    static int
    charCount(int codePoint)
    Determines the number of char values needed to represent the specified character (Unicode code point).
    char
    charValue()
    Returns the value of this Character object.
    static int
    codePointAt(char[] a, int index)
    Returns the code point at the given index of the char array.
    static int
    codePointAt(char[] a, int index, int limit)
    Returns the code point at the given index of the char array, where only array elements with index less than limit can be used.
    static int
    codePointAt(CharSequence seq, int index)
    Returns the code point at the given index of the CharSequence.
    static int
    codePointBefore(char[] a, int index)
    Returns the code point preceding the given index of the char array.
    static int
    codePointBefore(char[] a, int index, int start)
    Returns the code point preceding the given index of the char array, where only array elements with index greater than or equal to start can be used.
    static int
    codePointBefore(CharSequence seq, int index)
    Returns the code point preceding the given index of the CharSequence.
    static int
    codePointCount(char[] a, int offset, int count)
    Returns the number of Unicode code points in a subarray of the char array argument.
    static int
    codePointCount(CharSequence seq, int beginIndex, int endIndex)
    Returns the number of Unicode code points in the text range of the specified char sequence.
    static int
    codePointOf(String name)
    Returns the code point value of the Unicode character specified by the given character name.
    static int
    compare(char x, char y)
    Compares two char values numerically.
    int
    compareTo(Character anotherCharacter)
    Compares two Character objects numerically.
    Optional<DynamicConstantDesc<Character>>
    describeConstable()
    Returns an Optional containing the nominal descriptor for this instance.
    static int
    digit(char ch, int radix)
    Returns the numeric value of the character ch in the specified radix.
    static int
    digit(int codePoint, int radix)
    Returns the numeric value of the specified character (Unicode code point) in the specified radix.
    boolean
    equals(Object obj)
    Compares this object against the specified object.
    static char
    forDigit(int digit, int radix)
    Determines the character representation for a specific digit in the specified radix.
    static byte
    getDirectionality(char ch)
    Returns the Unicode directionality property for the given character.
    static byte
    getDirectionality(int codePoint)
    Returns the Unicode directionality property for the given character (Unicode code point).
    static String
    getName(int codePoint)
    Returns the name of the specified character codePoint, or null if the code point is unassigned.
    static int
    getNumericValue(char ch)
    Returns the int value that the specified Unicode character represents.
    static int
    getNumericValue(int codePoint)
    Returns the int value that the specified character (Unicode code point) represents.
    static int
    getType(char ch)
    Returns a value indicating a character's general category.
    static int
    getType(int codePoint)
    Returns a value indicating a character's general category.
    int
    hashCode()
    Returns a hash code for this Character; equal to the result of invoking charValue().
    static int
    hashCode(char value)
    Returns a hash code for a char value; compatible with Character.hashCode().
    static char
    highSurrogate(int codePoint)
    Returns the leading surrogate (a high surrogate code unit) of the surrogate pair representing the specified supplementary character (Unicode code point) in the UTF-16 encoding.
    static boolean
    isAlphabetic(int codePoint)
    Determines if the specified character (Unicode code point) is alphabetic.
    static boolean
    isBmpCodePoint(int codePoint)
    Determines whether the specified character (Unicode code point) is in the Basic Multilingual Plane (BMP).
    static boolean
    isDefined(char ch)
    Determines if a character is defined in Unicode.
    static boolean
    isDefined(int codePoint)
    Determines if a character (Unicode code point) is defined in Unicode.
    static boolean
    isDigit(char ch)
    Determines if the specified character is a digit.
    static boolean
    isDigit(int codePoint)
    Determines if the specified character (Unicode code point) is a digit.
    static boolean
    isHighSurrogate(char ch)
    Determines if the given char value is a Unicode high-surrogate code unit (also known as leading-surrogate code unit).
    static boolean
    isIdentifierIgnorable(char ch)
    Determines if the specified character should be regarded as an ignorable character in a Java identifier or a Unicode identifier.
    static boolean
    isIdentifierIgnorable(int codePoint)
    Determines if the specified character (Unicode code point) should be regarded as an ignorable character in a Java identifier or a Unicode identifier.
    static boolean
    isIdeographic(int codePoint)
    Determines if the specified character (Unicode code point) is a CJKV (Chinese, Japanese, Korean and Vietnamese) ideograph, as defined by the Unicode Standard.
    static boolean
    isISOControl(char ch)
    Determines if the specified character is an ISO control character.
    static boolean
    isISOControl(int codePoint)
    Determines if the referenced character (Unicode code point) is an ISO control character.
    static boolean
    isJavaIdentifierPart(char ch)
    Determines if the specified character may be part of a Java identifier as other than the first character.
    static boolean
    isJavaIdentifierPart(int codePoint)
    Determines if the character (Unicode code point) may be part of a Java identifier as other than the first character.
    static boolean
    isJavaIdentifierStart(char ch)
    Determines if the specified character is permissible as the first character in a Java identifier.
    static boolean
    isJavaIdentifierStart(int codePoint)
    Determines if the character (Unicode code point) is permissible as the first character in a Java identifier.
    static boolean
    isJavaLetter(char ch)
    Deprecated.
    Replaced by isJavaIdentifierStart(char).
    static boolean
    isJavaLetterOrDigit(char ch)
    Deprecated.
    Replaced by isJavaIdentifierPart(char).
    static boolean
    isLetter(char ch)
    Determines if the specified character is a letter.
    static boolean
    isLetter(int codePoint)
    Determines if the specified character (Unicode code point) is a letter.
    static boolean
    isLetterOrDigit(char ch)
    Determines if the specified character is a letter or digit.
    static boolean
    isLetterOrDigit(int codePoint)
    Determines if the specified character (Unicode code point) is a letter or digit.
    static boolean
    isLowerCase(char ch)
    Determines if the specified character is a lowercase character.
    static boolean
    isLowerCase(int codePoint)
    Determines if the specified character (Unicode code point) is a lowercase character.
    static boolean
    isLowSurrogate(char ch)
    Determines if the given char value is a Unicode low-surrogate code unit (also known as trailing-surrogate code unit).
    static boolean
    isMirrored(char ch)
    Determines whether the character is mirrored according to the Unicode specification.
    static boolean
    isMirrored(int codePoint)
    Determines whether the specified character (Unicode code point) is mirrored according to the Unicode specification.
    static boolean
    isSpace(char ch)
    Deprecated.
    Replaced by isWhitespace(char).
    static boolean
    isSpaceChar(char ch)
    Determines if the specified character is a Unicode space character.
    static boolean
    isSpaceChar(int codePoint)
    Determines if the specified character (Unicode code point) is a Unicode space character.
    static boolean
    isSupplementaryCodePoint(int codePoint)
    Determines whether the specified character (Unicode code point) is in the supplementary character range.
    static boolean
    isSurrogate(char ch)
    Determines if the given char value is a Unicode surrogate code unit.
    static boolean
    isSurrogatePair(char high, char low)
    Determines whether the specified pair of char values is a valid Unicode surrogate pair.
    static boolean
    isTitleCase(char ch)
    Determines if the specified character is a titlecase character.
    static boolean
    isTitleCase(int codePoint)
    Determines if the specified character (Unicode code point) is a titlecase character.
    static boolean
    isUnicodeIdentifierPart(char ch)
    Determines if the specified character may be part of a Unicode identifier as other than the first character.
    static boolean
    isUnicodeIdentifierPart(int codePoint)
    Determines if the specified character (Unicode code point) may be part of a Unicode identifier as other than the first character.
    static boolean
    isUnicodeIdentifierStart(char ch)
    Determines if the specified character is permissible as the first character in a Unicode identifier.
    static boolean
    isUnicodeIdentifierStart(int codePoint)
    Determines if the specified character (Unicode code point) is permissible as the first character in a Unicode identifier.
    static boolean
    isUpperCase(char ch)
    Determines if the specified character is an uppercase character.
    static boolean
    isUpperCase(int codePoint)
    Determines if the specified character (Unicode code point) is an uppercase character.
    static boolean
    isValidCodePoint(int codePoint)
    Determines whether the specified code point is a valid Unicode code point value.
    static boolean
    isWhitespace(char ch)
    Determines if the specified character is white space according to Java.
    static boolean
    isWhitespace(int codePoint)
    Determines if the specified character (Unicode code point) is white space according to Java.
    static char
    lowSurrogate(int codePoint)
    Returns the trailing surrogate (a low surrogate code unit) of the surrogate pair representing the specified supplementary character (Unicode code point) in the UTF-16 encoding.
    static int
    offsetByCodePoints(char[] a, int start, int count, int index, int codePointOffset)
    Returns the index within the given char subarray that is offset from the given index by codePointOffset code points.
    static int
    offsetByCodePoints(CharSequence seq, int index, int codePointOffset)
    Returns the index within the given char sequence that is offset from the given index by codePointOffset code points.
    static char
    reverseBytes(char ch)
    Returns the value obtained by reversing the order of the bytes in the specified char value.
    static char[]
    toChars(int codePoint)
    Converts the specified character (Unicode code point) to its UTF-16 representation stored in a char array.
    static int
    toChars(int codePoint, char[] dst, int dstIndex)
    Converts the specified character (Unicode code point) to its UTF-16 representation.
    static int
    toCodePoint(char high, char low)
    Converts the specified surrogate pair to its supplementary code point value.
    static char
    toLowerCase(char ch)
    Converts the character argument to lowercase using case mapping information from the UnicodeData file.
    static int
    toLowerCase(int codePoint)
    Converts the character (Unicode code point) argument to lowercase using case mapping information from the UnicodeData file.
    String
    toString()
    Returns a String object representing this Character's value.
    static String
    toString(char c)
    Returns a String object representing the specified char.
    static String
    toString(int codePoint)
    Returns a String object representing the specified character (Unicode code point).
    static char
    toTitleCase(char ch)
    Converts the character argument to titlecase using case mapping information from the UnicodeData file.
    static int
    toTitleCase(int codePoint)
    Converts the character (Unicode code point) argument to titlecase using case mapping information from the UnicodeData file.
    static char
    toUpperCase(char ch)
    Converts the character argument to uppercase using case mapping information from the UnicodeData file.
    static int
    toUpperCase(int codePoint)
    Converts the character (Unicode code point) argument to uppercase using case mapping information from the UnicodeData file.
    static Character
    valueOf(char c)
    Returns a Character instance representing the specified char value.

    Methods declared in class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • MIN_RADIX

      public static final int MIN_RADIX
      The minimum radix available for conversion to and from strings. The constant value of this field is the smallest value permitted for the radix argument in radix-conversion methods such as the digit method, the forDigit method, and the toString method of class Integer.
      See Also:

    • MAX_RADIX

      public static final int MAX_RADIX
      The maximum radix available for conversion to and from strings. The constant value of this field is the largest value permitted for the radix argument in radix-conversion methods such as the digit method, the forDigit method, and the toString method of class Integer.
      See Also:

    • MIN_VALUE

      public static final char MIN_VALUE
      The constant value of this field is the smallest value of type char, '\u0000'.
      Since:
      1.0.2
      See Also:

    • MAX_VALUE

      public static final char MAX_VALUE
      The constant value of this field is the largest value of type char, '\uFFFF'.
      Since:
      1.0.2
      See Also:

    • TYPE

      public static final Class<Character> TYPE
      The Class instance representing the primitive type char.
      Since:
      1.1

    • UNASSIGNED

      public static final byte UNASSIGNED
      General category "Cn" in the Unicode specification.
      Since:
      1.1
      See Also:

    • UPPERCASE_LETTER

      public static final byte UPPERCASE_LETTER
      General category "Lu" in the Unicode specification.
      Since:
      1.1
      See Also:

    • LOWERCASE_LETTER

      public static final byte LOWERCASE_LETTER
      General category "Ll" in the Unicode specification.
      Since:
      1.1
      See Also:

    • TITLECASE_LETTER

      public static final byte TITLECASE_LETTER
      General category "Lt" in the Unicode specification.
      Since:
      1.1
      See Also:

    • MODIFIER_LETTER

      public static final byte MODIFIER_LETTER
      General category "Lm" in the Unicode specification.
      Since:
      1.1
      See Also:

    • OTHER_LETTER

      public static final byte OTHER_LETTER
      General category "Lo" in the Unicode specification.
      Since:
      1.1
      See Also:

    • NON_SPACING_MARK

      public static final byte NON_SPACING_MARK
      General category "Mn" in the Unicode specification.
      Since:
      1.1
      See Also:

    • ENCLOSING_MARK

      public static final byte ENCLOSING_MARK
      General category "Me" in the Unicode specification.
      Since:
      1.1
      See Also:

    • COMBINING_SPACING_MARK

      public static final byte COMBINING_SPACING_MARK
      General category "Mc" in the Unicode specification.
      Since:
      1.1
      See Also:

    • DECIMAL_DIGIT_NUMBER

      public static final byte DECIMAL_DIGIT_NUMBER
      General category "Nd" in the Unicode specification.
      Since:
      1.1
      See Also:

    • LETTER_NUMBER

      public static final byte LETTER_NUMBER
      General category "Nl" in the Unicode specification.
      Since:
      1.1
      See Also:

    • OTHER_NUMBER

      public static final byte OTHER_NUMBER
      General category "No" in the Unicode specification.
      Since:
      1.1
      See Also:

    • SPACE_SEPARATOR

      public static final byte SPACE_SEPARATOR
      General category "Zs" in the Unicode specification.
      Since:
      1.1
      See Also:

    • LINE_SEPARATOR

      public static final byte LINE_SEPARATOR
      General category "Zl" in the Unicode specification.
      Since:
      1.1
      See Also:

    • PARAGRAPH_SEPARATOR

      public static final byte PARAGRAPH_SEPARATOR
      General category "Zp" in the Unicode specification.
      Since:
      1.1
      See Also:

    • CONTROL

      public static final byte CONTROL
      General category "Cc" in the Unicode specification.
      Since:
      1.1
      See Also:

    • FORMAT

      public static final byte FORMAT
      General category "Cf" in the Unicode specification.
      Since:
      1.1
      See Also:

    • PRIVATE_USE

      public static final byte PRIVATE_USE
      General category "Co" in the Unicode specification.
      Since:
      1.1
      See Also:

    • SURROGATE

      public static final byte SURROGATE
      General category "Cs" in the Unicode specification.
      Since:
      1.1
      See Also:

    • DASH_PUNCTUATION

      public static final byte DASH_PUNCTUATION
      General category "Pd" in the Unicode specification.
      Since:
      1.1
      See Also:

    • START_PUNCTUATION

      public static final byte START_PUNCTUATION
      General category "Ps" in the Unicode specification.
      Since:
      1.1
      See Also:

    • END_PUNCTUATION

      public static final byte END_PUNCTUATION
      General category "Pe" in the Unicode specification.
      Since:
      1.1
      See Also:

    • CONNECTOR_PUNCTUATION

      public static final byte CONNECTOR_PUNCTUATION
      General category "Pc" in the Unicode specification.
      Since:
      1.1
      See Also:

    • OTHER_PUNCTUATION

      public static final byte OTHER_PUNCTUATION
      General category "Po" in the Unicode specification.
      Since:
      1.1
      See Also:

    • MATH_SYMBOL

      public static final byte MATH_SYMBOL
      General category "Sm" in the Unicode specification.
      Since:
      1.1
      See Also:

    • CURRENCY_SYMBOL

      public static final byte CURRENCY_SYMBOL
      General category "Sc" in the Unicode specification.
      Since:
      1.1
      See Also:

    • MODIFIER_SYMBOL

      public static final byte MODIFIER_SYMBOL
      General category "Sk" in the Unicode specification.
      Since:
      1.1
      See Also:

    • OTHER_SYMBOL

      public static final byte OTHER_SYMBOL
      General category "So" in the Unicode specification.
      Since:
      1.1
      See Also:

    • INITIAL_QUOTE_PUNCTUATION

      public static final byte INITIAL_QUOTE_PUNCTUATION
      General category "Pi" in the Unicode specification.
      Since:
      1.4
      See Also:

    • FINAL_QUOTE_PUNCTUATION

      public static final byte FINAL_QUOTE_PUNCTUATION
      General category "Pf" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_UNDEFINED

      public static final byte DIRECTIONALITY_UNDEFINED
      Undefined bidirectional character type. Undefined char values have undefined directionality in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_LEFT_TO_RIGHT

      public static final byte DIRECTIONALITY_LEFT_TO_RIGHT
      Strong bidirectional character type "L" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_RIGHT_TO_LEFT

      public static final byte DIRECTIONALITY_RIGHT_TO_LEFT
      Strong bidirectional character type "R" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC

      public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC
      Strong bidirectional character type "AL" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_EUROPEAN_NUMBER

      public static final byte DIRECTIONALITY_EUROPEAN_NUMBER
      Weak bidirectional character type "EN" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR

      public static final byte DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR
      Weak bidirectional character type "ES" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR

      public static final byte DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR
      Weak bidirectional character type "ET" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_ARABIC_NUMBER

      public static final byte DIRECTIONALITY_ARABIC_NUMBER
      Weak bidirectional character type "AN" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_COMMON_NUMBER_SEPARATOR

      public static final byte DIRECTIONALITY_COMMON_NUMBER_SEPARATOR
      Weak bidirectional character type "CS" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_NONSPACING_MARK

      public static final byte DIRECTIONALITY_NONSPACING_MARK
      Weak bidirectional character type "NSM" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_BOUNDARY_NEUTRAL

      public static final byte DIRECTIONALITY_BOUNDARY_NEUTRAL
      Weak bidirectional character type "BN" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_PARAGRAPH_SEPARATOR

      public static final byte DIRECTIONALITY_PARAGRAPH_SEPARATOR
      Neutral bidirectional character type "B" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_SEGMENT_SEPARATOR

      public static final byte DIRECTIONALITY_SEGMENT_SEPARATOR
      Neutral bidirectional character type "S" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_WHITESPACE

      public static final byte DIRECTIONALITY_WHITESPACE
      Neutral bidirectional character type "WS" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_OTHER_NEUTRALS

      public static final byte DIRECTIONALITY_OTHER_NEUTRALS
      Neutral bidirectional character type "ON" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING

      public static final byte DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING
      Strong bidirectional character type "LRE" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE

      public static final byte DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE
      Strong bidirectional character type "LRO" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING

      public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING
      Strong bidirectional character type "RLE" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE

      public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE
      Strong bidirectional character type "RLO" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_POP_DIRECTIONAL_FORMAT

      public static final byte DIRECTIONALITY_POP_DIRECTIONAL_FORMAT
      Weak bidirectional character type "PDF" in the Unicode specification.
      Since:
      1.4
      See Also:

    • DIRECTIONALITY_LEFT_TO_RIGHT_ISOLATE

      public static final byte DIRECTIONALITY_LEFT_TO_RIGHT_ISOLATE
      Weak bidirectional character type "LRI" in the Unicode specification.
      Since:
      9
      See Also:

    • DIRECTIONALITY_RIGHT_TO_LEFT_ISOLATE

      public static final byte DIRECTIONALITY_RIGHT_TO_LEFT_ISOLATE
      Weak bidirectional character type "RLI" in the Unicode specification.
      Since:
      9
      See Also:

    • DIRECTIONALITY_FIRST_STRONG_ISOLATE

      public static final byte DIRECTIONALITY_FIRST_STRONG_ISOLATE
      Weak bidirectional character type "FSI" in the Unicode specification.
      Since:
      9
      See Also:

    • DIRECTIONALITY_POP_DIRECTIONAL_ISOLATE

      public static final byte DIRECTIONALITY_POP_DIRECTIONAL_ISOLATE
      Weak bidirectional character type "PDI" in the Unicode specification.
      Since:
      9
      See Also:

    • MIN_HIGH_SURROGATE

      public static final char MIN_HIGH_SURROGATE
      The minimum value of a Unicode high-surrogate code unit in the UTF-16 encoding, constant '\uD800'. A high-surrogate is also known as a leading-surrogate.
      Since:
      1.5
      See Also:

    • MAX_HIGH_SURROGATE

      public static final char MAX_HIGH_SURROGATE
      The maximum value of a Unicode high-surrogate code unit in the UTF-16 encoding, constant '\uDBFF'. A high-surrogate is also known as a leading-surrogate.
      Since:
      1.5
      See Also:

    • MIN_LOW_SURROGATE

      public static final char MIN_LOW_SURROGATE
      The minimum value of a Unicode low-surrogate code unit in the UTF-16 encoding, constant '\uDC00'. A low-surrogate is also known as a trailing-surrogate.
      Since:
      1.5
      See Also:

    • MAX_LOW_SURROGATE

      public static final char MAX_LOW_SURROGATE
      The maximum value of a Unicode low-surrogate code unit in the UTF-16 encoding, constant '\uDFFF'. A low-surrogate is also known as a trailing-surrogate.
      Since:
      1.5
      See Also:

    • MIN_SURROGATE

      public static final char MIN_SURROGATE
      The minimum value of a Unicode surrogate code unit in the UTF-16 encoding, constant '\uD800'.
      Since:
      1.5
      See Also:

    • MAX_SURROGATE

      public static final char MAX_SURROGATE
      The maximum value of a Unicode surrogate code unit in the UTF-16 encoding, constant '\uDFFF'.
      Since:
      1.5
      See Also:

    • MIN_SUPPLEMENTARY_CODE_POINT

      public static final int MIN_SUPPLEMENTARY_CODE_POINT
      The minimum value of a Unicode supplementary code point, constant U+10000.
      Since:
      1.5
      See Also:

    • MIN_CODE_POINT

      public static final int MIN_CODE_POINT
      The minimum value of a Unicode code point, constant U+0000.
      Since:
      1.5
      See Also:

    • MAX_CODE_POINT

      public static final int MAX_CODE_POINT
      The maximum value of a Unicode code point, constant U+10FFFF.
      Since:
      1.5
      See Also:

    • SIZE

      public static final int SIZE
      The number of bits used to represent a char value in unsigned binary form, constant 16.
      Since:
      1.5
      See Also:

    • BYTES

      public static final int BYTES
      The number of bytes used to represent a char value in unsigned binary form.
      Since:
      1.8
      See Also:

  • Constructor Details

    • Character

      @Deprecated(since="9", forRemoval=true) public Character(char value)
      Deprecated, for removal: This API element is subject to removal in a future version.
      It is rarely appropriate to use this constructor. The static factory valueOf(char) is generally a better choice, as it is likely to yield significantly better space and time performance.
      Constructs a newly allocated Character object that represents the specified char value.
      Parameters:
      value - the value to be represented by the Character object.

  • Method Details

    • describeConstable

      public Optional<DynamicConstantDesc<Character>> describeConstable()
      Returns an Optional containing the nominal descriptor for this instance.
      Specified by:
      describeConstable in interface Constable
      Returns:
      an Optional describing the Character instance
      Since:
      15

    • valueOf

      public static Character valueOf(char c)
      Returns a Character instance representing the specified char value. If a new Character instance is not required, this method should generally be used in preference to the constructor Character(char), 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 '\u0000' to '\u007F', inclusive, and may cache other values outside of this range.
      Parameters:
      c - a char value.
      Returns:
      a Character instance representing c.
      Since:
      1.5

    • charValue

      public char charValue()
      Returns the value of this Character object.
      Returns:
      the primitive char value represented by this object.

    • hashCode

      public int hashCode()
      Returns a hash code for this Character; equal to the result of invoking charValue().
      Overrides:
      hashCode in class Object
      Returns:
      a hash code value for this Character
      See Also:

    • hashCode

      public static int hashCode(char value)
      Returns a hash code for a char value; compatible with Character.hashCode().
      Parameters:
      value - The char for which to return a hash code.
      Returns:
      a hash code value for a char value.
      Since:
      1.8

    • equals

      public boolean equals(Object obj)
      Compares this object against the specified object. The result is true if and only if the argument is not null and is a Character object that represents the same char 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:

    • toString

      public String toString()
      Returns a String object representing this Character's value. The result is a string of length 1 whose sole component is the primitive char value represented by this Character object.
      Overrides:
      toString in class Object
      Returns:
      a string representation of this object.

    • toString

      public static String toString(char c)
      Returns a String object representing the specified char. The result is a string of length 1 consisting solely of the specified char.
      API Note:
      This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the toString(int) method.
      Parameters:
      c - the char to be converted
      Returns:
      the string representation of the specified char
      Since:
      1.4

    • toString

      public static String toString(int codePoint)
      Returns a String object representing the specified character (Unicode code point). The result is a string of length 1 or 2, consisting solely of the specified codePoint.
      Parameters:
      codePoint - the codePoint to be converted
      Returns:
      the string representation of the specified codePoint
      Throws:
      IllegalArgumentException - if the specified codePoint is not a valid Unicode code point.
      Since:
      11

    • isValidCodePoint

      public static boolean isValidCodePoint(int codePoint)
      Determines whether the specified code point is a valid Unicode code point value.
      Parameters:
      codePoint - the Unicode code point to be tested
      Returns:
      true if the specified code point value is between MIN_CODE_POINT and MAX_CODE_POINT inclusive; false otherwise.
      Since:
      1.5

    • isBmpCodePoint

      public static boolean isBmpCodePoint(int codePoint)
      Determines whether the specified character (Unicode code point) is in the Basic Multilingual Plane (BMP). Such code points can be represented using a single char.
      Parameters:
      codePoint - the character (Unicode code point) to be tested
      Returns:
      true if the specified code point is between MIN_VALUE and MAX_VALUE inclusive; false otherwise.
      Since:
      1.7

    • isSupplementaryCodePoint

      public static boolean isSupplementaryCodePoint(int codePoint)
      Determines whether the specified character (Unicode code point) is in the supplementary character range.
      Parameters:
      codePoint - the character (Unicode code point) to be tested
      Returns:
      true if the specified code point is between MIN_SUPPLEMENTARY_CODE_POINT and MAX_CODE_POINT inclusive; false otherwise.
      Since:
      1.5

    • isHighSurrogate

      public static boolean isHighSurrogate(char ch)
      Determines if the given char value is a Unicode high-surrogate code unit (also known as leading-surrogate code unit).

      Such values do not represent characters by themselves, but are used in the representation of supplementary characters in the UTF-16 encoding.

      Parameters:
      ch - the char value to be tested.
      Returns:
      true if the char value is between MIN_HIGH_SURROGATE and MAX_HIGH_SURROGATE inclusive; false otherwise.
      Since:
      1.5
      See Also:

    • isLowSurrogate

      public static boolean isLowSurrogate(char ch)
      Determines if the given char value is a Unicode low-surrogate code unit (also known as trailing-surrogate code unit).

      Such values do not represent characters by themselves, but are used in the representation of supplementary characters in the UTF-16 encoding.

      Parameters:
      ch - the char value to be tested.
      Returns:
      true if the char value is between MIN_LOW_SURROGATE and MAX_LOW_SURROGATE inclusive; false otherwise.
      Since:
      1.5
      See Also:

    • isSurrogate

      public static boolean isSurrogate(char ch)
      Determines if the given char value is a Unicode surrogate code unit.

      Such values do not represent characters by themselves, but are used in the representation of supplementary characters in the UTF-16 encoding.

      A char value is a surrogate code unit if and only if it is either a low-surrogate code unit or a high-surrogate code unit.

      Parameters:
      ch - the char value to be tested.
      Returns:
      true if the char value is between MIN_SURROGATE and MAX_SURROGATE inclusive; false otherwise.
      Since:
      1.7

    • isSurrogatePair

      public static boolean isSurrogatePair(char high, char low)
      Determines whether the specified pair of char values is a valid Unicode surrogate pair.

      This method is equivalent to the expression: 

      
 isHighSurrogate(high) && isLowSurrogate(low)
      Parameters:
      high - the high-surrogate code value to be tested
      low - the low-surrogate code value to be tested
      Returns:
      true if the specified high and low-surrogate code values represent a valid surrogate pair; false otherwise.
      Since:
      1.5

    • charCount

      public static int charCount(int codePoint)
      Determines the number of char values needed to represent the specified character (Unicode code point). If the specified character is equal to or greater than 0x10000, then the method returns 2. Otherwise, the method returns 1.

      This method doesn't validate the specified character to be a valid Unicode code point. The caller must validate the character value using isValidCodePoint if necessary.

      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      2 if the character is a valid supplementary character; 1 otherwise.
      Since:
      1.5
      See Also:

    • toCodePoint

      public static int toCodePoint(char high, char low)
      Converts the specified surrogate pair to its supplementary code point value. This method does not validate the specified surrogate pair. The caller must validate it using isSurrogatePair if necessary.
      Parameters:
      high - the high-surrogate code unit
      low - the low-surrogate code unit
      Returns:
      the supplementary code point composed from the specified surrogate pair.
      Since:
      1.5

    • codePointAt

      public static int codePointAt(CharSequence seq, int index)
      Returns the code point at the given index of the CharSequence. If the char value at the given index in the CharSequence is in the high-surrogate range, the following index is less than the length of the CharSequence, and the char value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at the given index is returned.
      Parameters:
      seq - a sequence of char values (Unicode code units)
      index - the index to the char values (Unicode code units) in seq to be converted
      Returns:
      the Unicode code point at the given index
      Throws:
      NullPointerException - if seq is null.
      IndexOutOfBoundsException - if the value index is negative or not less than seq.length().
      Since:
      1.5

    • codePointAt

      public static int codePointAt(char[] a, int index)
      Returns the code point at the given index of the char array. If the char value at the given index in the char array is in the high-surrogate range, the following index is less than the length of the char array, and the char value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at the given index is returned.
      Parameters:
      a - the char array
      index - the index to the char values (Unicode code units) in the char array to be converted
      Returns:
      the Unicode code point at the given index
      Throws:
      NullPointerException - if a is null.
      IndexOutOfBoundsException - if the value index is negative or not less than the length of the char array.
      Since:
      1.5

    • codePointAt

      public static int codePointAt(char[] a, int index, int limit)
      Returns the code point at the given index of the char array, where only array elements with index less than limit can be used. If the char value at the given index in the char array is in the high-surrogate range, the following index is less than the limit, and the char value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at the given index is returned.
      Parameters:
      a - the char array
      index - the index to the char values (Unicode code units) in the char array to be converted
      limit - the index after the last array element that can be used in the char array
      Returns:
      the Unicode code point at the given index
      Throws:
      NullPointerException - if a is null.
      IndexOutOfBoundsException - if the index argument is negative or not less than the limit argument, or if the limit argument is negative or greater than the length of the char array.
      Since:
      1.5

    • codePointBefore

      public static int codePointBefore(CharSequence seq, int index)
      Returns the code point preceding the given index of the CharSequence. If the char value at (index - 1) in the CharSequence is in the low-surrogate range, (index - 2) is not negative, and the char value at (index - 2) in the CharSequence is in the high-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at (index - 1) is returned.
      Parameters:
      seq - the CharSequence instance
      index - the index following the code point that should be returned
      Returns:
      the Unicode code point value before the given index.
      Throws:
      NullPointerException - if seq is null.
      IndexOutOfBoundsException - if the index argument is less than 1 or greater than seq.length().
      Since:
      1.5

    • codePointBefore

      public static int codePointBefore(char[] a, int index)
      Returns the code point preceding the given index of the char array. If the char value at (index - 1) in the char array is in the low-surrogate range, (index - 2) is not negative, and the char value at (index - 2) in the char array is in the high-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at (index - 1) is returned.
      Parameters:
      a - the char array
      index - the index following the code point that should be returned
      Returns:
      the Unicode code point value before the given index.
      Throws:
      NullPointerException - if a is null.
      IndexOutOfBoundsException - if the index argument is less than 1 or greater than the length of the char array
      Since:
      1.5

    • codePointBefore

      public static int codePointBefore(char[] a, int index, int start)
      Returns the code point preceding the given index of the char array, where only array elements with index greater than or equal to start can be used. If the char value at (index - 1) in the char array is in the low-surrogate range, (index - 2) is not less than start, and the char value at (index - 2) in the char array is in the high-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at (index - 1) is returned.
      Parameters:
      a - the char array
      index - the index following the code point that should be returned
      start - the index of the first array element in the char array
      Returns:
      the Unicode code point value before the given index.
      Throws:
      NullPointerException - if a is null.
      IndexOutOfBoundsException - if the index argument is not greater than the start argument or is greater than the length of the char array, or if the start argument is negative or not less than the length of the char array.
      Since:
      1.5

    • highSurrogate

      public static char highSurrogate(int codePoint)
      Returns the leading surrogate (a high surrogate code unit) of the surrogate pair representing the specified supplementary character (Unicode code point) in the UTF-16 encoding. If the specified character is not a supplementary character, an unspecified char is returned.

      If isSupplementaryCodePoint(x) is true, then isHighSurrogate(highSurrogate(x)) and toCodePoint(highSurrogate(x), lowSurrogate(x)) == x are also always true.

      Parameters:
      codePoint - a supplementary character (Unicode code point)
      Returns:
      the leading surrogate code unit used to represent the character in the UTF-16 encoding
      Since:
      1.7

    • lowSurrogate

      public static char lowSurrogate(int codePoint)
      Returns the trailing surrogate (a low surrogate code unit) of the surrogate pair representing the specified supplementary character (Unicode code point) in the UTF-16 encoding. If the specified character is not a supplementary character, an unspecified char is returned.

      If isSupplementaryCodePoint(x) is true, then isLowSurrogate(lowSurrogate(x)) and toCodePoint(highSurrogate(x), lowSurrogate(x)) == x are also always true.

      Parameters:
      codePoint - a supplementary character (Unicode code point)
      Returns:
      the trailing surrogate code unit used to represent the character in the UTF-16 encoding
      Since:
      1.7

    • toChars

      public static int toChars(int codePoint, char[] dst, int dstIndex)
      Converts the specified character (Unicode code point) to its UTF-16 representation. If the specified code point is a BMP (Basic Multilingual Plane or Plane 0) value, the same value is stored in dst[dstIndex], and 1 is returned. If the specified code point is a supplementary character, its surrogate values are stored in dst[dstIndex] (high-surrogate) and dst[dstIndex+1] (low-surrogate), and 2 is returned.
      Parameters:
      codePoint - the character (Unicode code point) to be converted.
      dst - an array of char in which the codePoint's UTF-16 value is stored.
      dstIndex - the start index into the dst array where the converted value is stored.
      Returns:
      1 if the code point is a BMP code point, 2 if the code point is a supplementary code point.
      Throws:
      IllegalArgumentException - if the specified codePoint is not a valid Unicode code point.
      NullPointerException - if the specified dst is null.
      IndexOutOfBoundsException - if dstIndex is negative or not less than dst.length, or if dst at dstIndex doesn't have enough array element(s) to store the resulting char value(s). (If dstIndex is equal to dst.length-1 and the specified codePoint is a supplementary character, the high-surrogate value is not stored in dst[dstIndex].)
      Since:
      1.5

    • toChars

      public static char[] toChars(int codePoint)
      Converts the specified character (Unicode code point) to its UTF-16 representation stored in a char array. If the specified code point is a BMP (Basic Multilingual Plane or Plane 0) value, the resulting char array has the same value as codePoint. If the specified code point is a supplementary code point, the resulting char array has the corresponding surrogate pair.
      Parameters:
      codePoint - a Unicode code point
      Returns:
      a char array having codePoint's UTF-16 representation.
      Throws:
      IllegalArgumentException - if the specified codePoint is not a valid Unicode code point.
      Since:
      1.5

    • codePointCount

      public static int codePointCount(CharSequence seq, int beginIndex, int endIndex)
      Returns the number of Unicode code points in the text range of the specified char sequence. The text range begins at the specified beginIndex and extends to the char at index endIndex - 1. Thus the length (in chars) of the text range is endIndex-beginIndex. Unpaired surrogates within the text range count as one code point each.
      Parameters:
      seq - the char sequence
      beginIndex - the index to the first char of the text range.
      endIndex - the index after the last char of the text range.
      Returns:
      the number of Unicode code points in the specified text range
      Throws:
      NullPointerException - if seq is null.
      IndexOutOfBoundsException - if the beginIndex is negative, or endIndex is larger than the length of the given sequence, or beginIndex is larger than endIndex.
      Since:
      1.5

    • codePointCount

      public static int codePointCount(char[] a, int offset, int count)
      Returns the number of Unicode code points in a subarray of the char array argument. The offset argument is the index of the first char of the subarray and the count argument specifies the length of the subarray in chars. Unpaired surrogates within the subarray count as one code point each.
      Parameters:
      a - the char array
      offset - the index of the first char in the given char array
      count - the length of the subarray in chars
      Returns:
      the number of Unicode code points in the specified subarray
      Throws:
      NullPointerException - if a is null.
      IndexOutOfBoundsException - if offset or count is negative, or if offset + count is larger than the length of the given array.
      Since:
      1.5

    • offsetByCodePoints

      public static int offsetByCodePoints(CharSequence seq, int index, int codePointOffset)
      Returns the index within the given char sequence that is offset from the given index by codePointOffset code points. Unpaired surrogates within the text range given by index and codePointOffset count as one code point each.
      Parameters:
      seq - the char sequence
      index - the index to be offset
      codePointOffset - the offset in code points
      Returns:
      the index within the char sequence
      Throws:
      NullPointerException - if seq is null.
      IndexOutOfBoundsException - if index is negative or larger than the length of the char sequence, or if codePointOffset is positive and the subsequence starting with index has fewer than codePointOffset code points, or if codePointOffset is negative and the subsequence before index has fewer than the absolute value of codePointOffset code points.
      Since:
      1.5

    • offsetByCodePoints

      public static int offsetByCodePoints(char[] a, int start, int count, int index, int codePointOffset)
      Returns the index within the given char subarray that is offset from the given index by codePointOffset code points. The start and count arguments specify a subarray of the char array. Unpaired surrogates within the text range given by index and codePointOffset count as one code point each.
      Parameters:
      a - the char array
      start - the index of the first char of the subarray
      count - the length of the subarray in chars
      index - the index to be offset
      codePointOffset - the offset in code points
      Returns:
      the index within the subarray
      Throws:
      NullPointerException - if a is null.
      IndexOutOfBoundsException - if start or count is negative, or if start + count is larger than the length of the given array, or if index is less than start or larger then start + count, or if codePointOffset is positive and the text range starting with index and ending with start + count - 1 has fewer than codePointOffset code points, or if codePointOffset is negative and the text range starting with start and ending with index - 1 has fewer than the absolute value of codePointOffset code points.
      Since:
      1.5

    • isLowerCase

      public static boolean isLowerCase(char ch)
      Determines if the specified character is a lowercase character.

      A character is lowercase if its general category type, provided by Character.getType(ch), is LOWERCASE_LETTER, or it has contributory property Other_Lowercase as defined by the Unicode Standard.

      The following are examples of lowercase characters: 

       a b c d e f g h i j k l m n o p q r s t u v w x y z
 '\u00DF' '\u00E0' '\u00E1' '\u00E2' '\u00E3' '\u00E4' '\u00E5' '\u00E6'
 '\u00E7' '\u00E8' '\u00E9' '\u00EA' '\u00EB' '\u00EC' '\u00ED' '\u00EE'
 '\u00EF' '\u00F0' '\u00F1' '\u00F2' '\u00F3' '\u00F4' '\u00F5' '\u00F6'
 '\u00F8' '\u00F9' '\u00FA' '\u00FB' '\u00FC' '\u00FD' '\u00FE' '\u00FF'

      Many other Unicode characters are lowercase too.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isLowerCase(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is lowercase; false otherwise.
      See Also:

    • isLowerCase

      public static boolean isLowerCase(int codePoint)
      Determines if the specified character (Unicode code point) is a lowercase character.

      A character is lowercase if its general category type, provided by getType(codePoint), is LOWERCASE_LETTER, or it has contributory property Other_Lowercase as defined by the Unicode Standard.

      The following are examples of lowercase characters: 

       a b c d e f g h i j k l m n o p q r s t u v w x y z
 '\u00DF' '\u00E0' '\u00E1' '\u00E2' '\u00E3' '\u00E4' '\u00E5' '\u00E6'
 '\u00E7' '\u00E8' '\u00E9' '\u00EA' '\u00EB' '\u00EC' '\u00ED' '\u00EE'
 '\u00EF' '\u00F0' '\u00F1' '\u00F2' '\u00F3' '\u00F4' '\u00F5' '\u00F6'
 '\u00F8' '\u00F9' '\u00FA' '\u00FB' '\u00FC' '\u00FD' '\u00FE' '\u00FF'

      Many other Unicode characters are lowercase too.

      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is lowercase; false otherwise.
      Since:
      1.5
      See Also:

    • isUpperCase

      public static boolean isUpperCase(char ch)
      Determines if the specified character is an uppercase character.

      A character is uppercase if its general category type, provided by Character.getType(ch), is UPPERCASE_LETTER. or it has contributory property Other_Uppercase as defined by the Unicode Standard.

      The following are examples of uppercase characters: 

       A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 '\u00C0' '\u00C1' '\u00C2' '\u00C3' '\u00C4' '\u00C5' '\u00C6' '\u00C7'
 '\u00C8' '\u00C9' '\u00CA' '\u00CB' '\u00CC' '\u00CD' '\u00CE' '\u00CF'
 '\u00D0' '\u00D1' '\u00D2' '\u00D3' '\u00D4' '\u00D5' '\u00D6' '\u00D8'
 '\u00D9' '\u00DA' '\u00DB' '\u00DC' '\u00DD' '\u00DE'

      Many other Unicode characters are uppercase too.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isUpperCase(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is uppercase; false otherwise.
      Since:
      1.0
      See Also:

    • isUpperCase

      public static boolean isUpperCase(int codePoint)
      Determines if the specified character (Unicode code point) is an uppercase character.

      A character is uppercase if its general category type, provided by getType(codePoint), is UPPERCASE_LETTER, or it has contributory property Other_Uppercase as defined by the Unicode Standard.

      The following are examples of uppercase characters: 

       A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 '\u00C0' '\u00C1' '\u00C2' '\u00C3' '\u00C4' '\u00C5' '\u00C6' '\u00C7'
 '\u00C8' '\u00C9' '\u00CA' '\u00CB' '\u00CC' '\u00CD' '\u00CE' '\u00CF'
 '\u00D0' '\u00D1' '\u00D2' '\u00D3' '\u00D4' '\u00D5' '\u00D6' '\u00D8'
 '\u00D9' '\u00DA' '\u00DB' '\u00DC' '\u00DD' '\u00DE'

      Many other Unicode characters are uppercase too.

      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is uppercase; false otherwise.
      Since:
      1.5
      See Also:

    • isTitleCase

      public static boolean isTitleCase(char ch)
      Determines if the specified character is a titlecase character.

      A character is a titlecase character if its general category type, provided by Character.getType(ch), is TITLECASE_LETTER.

      Some characters look like pairs of Latin letters. For example, there is an uppercase letter that looks like "LJ" and has a corresponding lowercase letter that looks like "lj". A third form, which looks like "Lj", is the appropriate form to use when rendering a word in lowercase with initial capitals, as for a book title.

      These are some of the Unicode characters for which this method returns true:

      • LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON
      • LATIN CAPITAL LETTER L WITH SMALL LETTER J
      • LATIN CAPITAL LETTER N WITH SMALL LETTER J
      • LATIN CAPITAL LETTER D WITH SMALL LETTER Z

      Many other Unicode characters are titlecase too.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isTitleCase(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is titlecase; false otherwise.
      Since:
      1.0.2
      See Also:

    • isTitleCase

      public static boolean isTitleCase(int codePoint)
      Determines if the specified character (Unicode code point) is a titlecase character.

      A character is a titlecase character if its general category type, provided by getType(codePoint), is TITLECASE_LETTER.

      Some characters look like pairs of Latin letters. For example, there is an uppercase letter that looks like "LJ" and has a corresponding lowercase letter that looks like "lj". A third form, which looks like "Lj", is the appropriate form to use when rendering a word in lowercase with initial capitals, as for a book title.

      These are some of the Unicode characters for which this method returns true:

      • LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON
      • LATIN CAPITAL LETTER L WITH SMALL LETTER J
      • LATIN CAPITAL LETTER N WITH SMALL LETTER J
      • LATIN CAPITAL LETTER D WITH SMALL LETTER Z

      Many other Unicode characters are titlecase too.

      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is titlecase; false otherwise.
      Since:
      1.5
      See Also:

    • isDigit

      public static boolean isDigit(char ch)
      Determines if the specified character is a digit.

      A character is a digit if its general category type, provided by Character.getType(ch), is DECIMAL_DIGIT_NUMBER.

      Some Unicode character ranges that contain digits:

      • '\u0030' through '\u0039', ISO-LATIN-1 digits ('0' through '9')
      • '\u0660' through '\u0669', Arabic-Indic digits
      • '\u06F0' through '\u06F9', Extended Arabic-Indic digits
      • '\u0966' through '\u096F', Devanagari digits
      • '\uFF10' through '\uFF19', Fullwidth digits
      Many other character ranges contain digits as well.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isDigit(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is a digit; false otherwise.
      See Also:

    • isDigit

      public static boolean isDigit(int codePoint)
      Determines if the specified character (Unicode code point) is a digit.

      A character is a digit if its general category type, provided by getType(codePoint), is DECIMAL_DIGIT_NUMBER.

      Some Unicode character ranges that contain digits:

      • '\u0030' through '\u0039', ISO-LATIN-1 digits ('0' through '9')
      • '\u0660' through '\u0669', Arabic-Indic digits
      • '\u06F0' through '\u06F9', Extended Arabic-Indic digits
      • '\u0966' through '\u096F', Devanagari digits
      • '\uFF10' through '\uFF19', Fullwidth digits
      Many other character ranges contain digits as well.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is a digit; false otherwise.
      Since:
      1.5
      See Also:

    • isDefined

      public static boolean isDefined(char ch)
      Determines if a character is defined in Unicode.

      A character is defined if at least one of the following is true:

      • It has an entry in the UnicodeData file.
      • It has a value in a range defined by the UnicodeData file.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isDefined(int) method.

      Parameters:
      ch - the character to be tested
      Returns:
      true if the character has a defined meaning in Unicode; false otherwise.
      Since:
      1.0.2
      See Also:

    • isDefined

      public static boolean isDefined(int codePoint)
      Determines if a character (Unicode code point) is defined in Unicode.

      A character is defined if at least one of the following is true:

      • It has an entry in the UnicodeData file.
      • It has a value in a range defined by the UnicodeData file.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character has a defined meaning in Unicode; false otherwise.
      Since:
      1.5
      See Also:

    • isLetter

      public static boolean isLetter(char ch)
      Determines if the specified character is a letter.

      A character is considered to be a letter if its general category type, provided by Character.getType(ch), is any of the following:

      • UPPERCASE_LETTER
      • LOWERCASE_LETTER
      • TITLECASE_LETTER
      • MODIFIER_LETTER
      • OTHER_LETTER
      Not all letters have case. Many characters are letters but are neither uppercase nor lowercase nor titlecase.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isLetter(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is a letter; false otherwise.
      See Also:

    • isLetter

      public static boolean isLetter(int codePoint)
      Determines if the specified character (Unicode code point) is a letter.

      A character is considered to be a letter if its general category type, provided by getType(codePoint), is any of the following:

      • UPPERCASE_LETTER
      • LOWERCASE_LETTER
      • TITLECASE_LETTER
      • MODIFIER_LETTER
      • OTHER_LETTER
      Not all letters have case. Many characters are letters but are neither uppercase nor lowercase nor titlecase.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is a letter; false otherwise.
      Since:
      1.5
      See Also:

    • isLetterOrDigit

      public static boolean isLetterOrDigit(char ch)
      Determines if the specified character is a letter or digit.

      A character is considered to be a letter or digit if either Character.isLetter(char ch) or Character.isDigit(char ch) returns true for the character.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isLetterOrDigit(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is a letter or digit; false otherwise.
      Since:
      1.0.2
      See Also:

    • isLetterOrDigit

      public static boolean isLetterOrDigit(int codePoint)
      Determines if the specified character (Unicode code point) is a letter or digit.

      A character is considered to be a letter or digit if either isLetter(codePoint) or isDigit(codePoint) returns true for the character.

      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is a letter or digit; false otherwise.
      Since:
      1.5
      See Also:

    • isJavaLetter

      @Deprecated(since="1.1") public static boolean isJavaLetter(char ch)
      Deprecated.
      Replaced by isJavaIdentifierStart(char).
      Determines if the specified character is permissible as the first character in a Java identifier.

      A character may start a Java identifier if and only if one of the following conditions is true:

      • isLetter(ch) returns true
      • getType(ch) returns LETTER_NUMBER
      • ch is a currency symbol (such as '$')
      • ch is a connecting punctuation character (such as '_').
      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character may start a Java identifier; false otherwise.
      Since:
      1.0.2
      See Also:

    • isJavaLetterOrDigit

      @Deprecated(since="1.1") public static boolean isJavaLetterOrDigit(char ch)
      Deprecated.
      Replaced by isJavaIdentifierPart(char).
      Determines if the specified character may be part of a Java identifier as other than the first character.

      A character may be part of a Java identifier if and only if one of the following conditions is true:

      • it is a letter
      • it is a currency symbol (such as '$')
      • it is a connecting punctuation character (such as '_')
      • it is a digit
      • it is a numeric letter (such as a Roman numeral character)
      • it is a combining mark
      • it is a non-spacing mark
      • isIdentifierIgnorable returns true for the character.
      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character may be part of a Java identifier; false otherwise.
      Since:
      1.0.2
      See Also:

    • isAlphabetic

      public static boolean isAlphabetic(int codePoint)
      Determines if the specified character (Unicode code point) is alphabetic.

      A character is considered to be alphabetic if its general category type, provided by getType(codePoint), is any of the following:

      • UPPERCASE_LETTER
      • LOWERCASE_LETTER
      • TITLECASE_LETTER
      • MODIFIER_LETTER
      • OTHER_LETTER
      • LETTER_NUMBER
      or it has contributory property Other_Alphabetic as defined by the Unicode Standard.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is a Unicode alphabet character, false otherwise.
      Since:
      1.7

    • isIdeographic

      public static boolean isIdeographic(int codePoint)
      Determines if the specified character (Unicode code point) is a CJKV (Chinese, Japanese, Korean and Vietnamese) ideograph, as defined by the Unicode Standard.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is a Unicode ideograph character, false otherwise.
      Since:
      1.7

    • isJavaIdentifierStart

      public static boolean isJavaIdentifierStart(char ch)
      Determines if the specified character is permissible as the first character in a Java identifier.

      A character may start a Java identifier if and only if one of the following conditions is true:

      • isLetter(ch) returns true
      • getType(ch) returns LETTER_NUMBER
      • ch is a currency symbol (such as '$')
      • ch is a connecting punctuation character (such as '_').

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isJavaIdentifierStart(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character may start a Java identifier; false otherwise.
      Since:
      1.1
      See Also:

    • isJavaIdentifierStart

      public static boolean isJavaIdentifierStart(int codePoint)
      Determines if the character (Unicode code point) is permissible as the first character in a Java identifier.

      A character may start a Java identifier if and only if one of the following conditions is true:

      • isLetter(codePoint) returns true
      • getType(codePoint) returns LETTER_NUMBER
      • the referenced character is a currency symbol (such as '$')
      • the referenced character is a connecting punctuation character (such as '_').
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character may start a Java identifier; false otherwise.
      Since:
      1.5
      See Also:

    • isJavaIdentifierPart

      public static boolean isJavaIdentifierPart(char ch)
      Determines if the specified character may be part of a Java identifier as other than the first character.

      A character may be part of a Java identifier if any of the following conditions are true:

      • it is a letter
      • it is a currency symbol (such as '$')
      • it is a connecting punctuation character (such as '_')
      • it is a digit
      • it is a numeric letter (such as a Roman numeral character)
      • it is a combining mark
      • it is a non-spacing mark
      • isIdentifierIgnorable returns true for the character

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isJavaIdentifierPart(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character may be part of a Java identifier; false otherwise.
      Since:
      1.1
      See Also:

    • isJavaIdentifierPart

      public static boolean isJavaIdentifierPart(int codePoint)
      Determines if the character (Unicode code point) may be part of a Java identifier as other than the first character.

      A character may be part of a Java identifier if any of the following conditions are true:

      • it is a letter
      • it is a currency symbol (such as '$')
      • it is a connecting punctuation character (such as '_')
      • it is a digit
      • it is a numeric letter (such as a Roman numeral character)
      • it is a combining mark
      • it is a non-spacing mark
      • isIdentifierIgnorable(codePoint) returns true for the code point
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character may be part of a Java identifier; false otherwise.
      Since:
      1.5
      See Also:

    • isUnicodeIdentifierStart

      public static boolean isUnicodeIdentifierStart(char ch)
      Determines if the specified character is permissible as the first character in a Unicode identifier.

      A character may start a Unicode identifier if and only if one of the following conditions is true:

      This method conforms to UAX31-R1: Default Identifiers requirement of the Unicode Standard, with the following profile of UAX31: 

       Start := ID_Start + 'VERTICAL TILDE' (U+2E2F)
      'VERTICAL TILDE' is added to Start for backward compatibility.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isUnicodeIdentifierStart(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character may start a Unicode identifier; false otherwise.
      Since:
      1.1
      See Also:

    • isUnicodeIdentifierStart

      public static boolean isUnicodeIdentifierStart(int codePoint)
      Determines if the specified character (Unicode code point) is permissible as the first character in a Unicode identifier.

      A character may start a Unicode identifier if and only if one of the following conditions is true:

      This method conforms to UAX31-R1: Default Identifiers requirement of the Unicode Standard, with the following profile of UAX31: 

       Start := ID_Start + 'VERTICAL TILDE' (U+2E2F)
      'VERTICAL TILDE' is added to Start for backward compatibility.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character may start a Unicode identifier; false otherwise.
      Since:
      1.5
      See Also:

    • isUnicodeIdentifierPart

      public static boolean isUnicodeIdentifierPart(char ch)
      Determines if the specified character may be part of a Unicode identifier as other than the first character.

      A character may be part of a Unicode identifier if and only if one of the following statements is true:

      • it is a letter
      • it is a connecting punctuation character (such as '_')
      • it is a digit
      • it is a numeric letter (such as a Roman numeral character)
      • it is a combining mark
      • it is a non-spacing mark
      • isIdentifierIgnorable returns true for this character.
      • it is an Other_ID_Start character.
      • it is an Other_ID_Continue character.

      This method conforms to UAX31-R1: Default Identifiers requirement of the Unicode Standard, with the following profile of UAX31: 

       Continue := Start + ID_Continue + ignorable
 Medial := empty
 ignorable := isIdentifierIgnorable(char) returns true for the character
      ignorable is added to Continue for backward compatibility.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isUnicodeIdentifierPart(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character may be part of a Unicode identifier; false otherwise.
      Since:
      1.1
      See Also:

    • isUnicodeIdentifierPart

      public static boolean isUnicodeIdentifierPart(int codePoint)
      Determines if the specified character (Unicode code point) may be part of a Unicode identifier as other than the first character.

      A character may be part of a Unicode identifier if and only if one of the following statements is true:

      • it is a letter
      • it is a connecting punctuation character (such as '_')
      • it is a digit
      • it is a numeric letter (such as a Roman numeral character)
      • it is a combining mark
      • it is a non-spacing mark
      • isIdentifierIgnorable returns true for this character.
      • it is an Other_ID_Start character.
      • it is an Other_ID_Continue character.

      This method conforms to UAX31-R1: Default Identifiers requirement of the Unicode Standard, with the following profile of UAX31: 

       Continue := Start + ID_Continue + ignorable
 Medial := empty
 ignorable := isIdentifierIgnorable(int) returns true for the character
      ignorable is added to Continue for backward compatibility.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character may be part of a Unicode identifier; false otherwise.
      Since:
      1.5
      See Also:

    • isIdentifierIgnorable

      public static boolean isIdentifierIgnorable(char ch)
      Determines if the specified character should be regarded as an ignorable character in a Java identifier or a Unicode identifier.

      The following Unicode characters are ignorable in a Java identifier or a Unicode identifier:

      • ISO control characters that are not whitespace
        • '\u0000' through '\u0008'
        • '\u000E' through '\u001B'
        • '\u007F' through '\u009F'
      • all characters that have the FORMAT general category value

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isIdentifierIgnorable(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is an ignorable control character that may be part of a Java or Unicode identifier; false otherwise.
      Since:
      1.1
      See Also:

    • isIdentifierIgnorable

      public static boolean isIdentifierIgnorable(int codePoint)
      Determines if the specified character (Unicode code point) should be regarded as an ignorable character in a Java identifier or a Unicode identifier.

      The following Unicode characters are ignorable in a Java identifier or a Unicode identifier:

      • ISO control characters that are not whitespace
        • '\u0000' through '\u0008'
        • '\u000E' through '\u001B'
        • '\u007F' through '\u009F'
      • all characters that have the FORMAT general category value
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is an ignorable control character that may be part of a Java or Unicode identifier; false otherwise.
      Since:
      1.5
      See Also:

    • toLowerCase

      public static char toLowerCase(char ch)
      Converts the character argument to lowercase using case mapping information from the UnicodeData file.

      Note that Character.isLowerCase(Character.toLowerCase(ch)) does not always return true for some ranges of characters, particularly those that are symbols or ideographs.

      In general, String.toLowerCase() should be used to map characters to lowercase. String case mapping methods have several benefits over Character case mapping methods. String case mapping methods can perform locale-sensitive mappings, context-sensitive mappings, and 1:M character mappings, whereas the Character case mapping methods cannot.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the toLowerCase(int) method.

      Parameters:
      ch - the character to be converted.
      Returns:
      the lowercase equivalent of the character, if any; otherwise, the character itself.
      See Also:

    • toLowerCase

      public static int toLowerCase(int codePoint)
      Converts the character (Unicode code point) argument to lowercase using case mapping information from the UnicodeData file.

      Note that Character.isLowerCase(Character.toLowerCase(codePoint)) does not always return true for some ranges of characters, particularly those that are symbols or ideographs.

      In general, String.toLowerCase() should be used to map characters to lowercase. String case mapping methods have several benefits over Character case mapping methods. String case mapping methods can perform locale-sensitive mappings, context-sensitive mappings, and 1:M character mappings, whereas the Character case mapping methods cannot.

      Parameters:
      codePoint - the character (Unicode code point) to be converted.
      Returns:
      the lowercase equivalent of the character (Unicode code point), if any; otherwise, the character itself.
      Since:
      1.5
      See Also:

    • toUpperCase

      public static char toUpperCase(char ch)
      Converts the character argument to uppercase using case mapping information from the UnicodeData file.

      Note that Character.isUpperCase(Character.toUpperCase(ch)) does not always return true for some ranges of characters, particularly those that are symbols or ideographs.

      In general, String.toUpperCase() should be used to map characters to uppercase. String case mapping methods have several benefits over Character case mapping methods. String case mapping methods can perform locale-sensitive mappings, context-sensitive mappings, and 1:M character mappings, whereas the Character case mapping methods cannot.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the toUpperCase(int) method.

      Parameters:
      ch - the character to be converted.
      Returns:
      the uppercase equivalent of the character, if any; otherwise, the character itself.
      See Also:

    • toUpperCase

      public static int toUpperCase(int codePoint)
      Converts the character (Unicode code point) argument to uppercase using case mapping information from the UnicodeData file.

      Note that Character.isUpperCase(Character.toUpperCase(codePoint)) does not always return true for some ranges of characters, particularly those that are symbols or ideographs.

      In general, String.toUpperCase() should be used to map characters to uppercase. String case mapping methods have several benefits over Character case mapping methods. String case mapping methods can perform locale-sensitive mappings, context-sensitive mappings, and 1:M character mappings, whereas the Character case mapping methods cannot.

      Parameters:
      codePoint - the character (Unicode code point) to be converted.
      Returns:
      the uppercase equivalent of the character, if any; otherwise, the character itself.
      Since:
      1.5
      See Also:

    • toTitleCase

      public static char toTitleCase(char ch)
      Converts the character argument to titlecase using case mapping information from the UnicodeData file. If a character has no explicit titlecase mapping and is not itself a titlecase char according to UnicodeData, then the uppercase mapping is returned as an equivalent titlecase mapping. If the char argument is already a titlecase char, the same char value will be returned.

      Note that Character.isTitleCase(Character.toTitleCase(ch)) does not always return true for some ranges of characters.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the toTitleCase(int) method.

      Parameters:
      ch - the character to be converted.
      Returns:
      the titlecase equivalent of the character, if any; otherwise, the character itself.
      Since:
      1.0.2
      See Also:

    • toTitleCase

      public static int toTitleCase(int codePoint)
      Converts the character (Unicode code point) argument to titlecase using case mapping information from the UnicodeData file. If a character has no explicit titlecase mapping and is not itself a titlecase char according to UnicodeData, then the uppercase mapping is returned as an equivalent titlecase mapping. If the character argument is already a titlecase character, the same character value will be returned.

      Note that Character.isTitleCase(Character.toTitleCase(codePoint)) does not always return true for some ranges of characters.

      Parameters:
      codePoint - the character (Unicode code point) to be converted.
      Returns:
      the titlecase equivalent of the character, if any; otherwise, the character itself.
      Since:
      1.5
      See Also:

    • digit

      public static int digit(char ch, int radix)
      Returns the numeric value of the character ch in the specified radix.

      If the radix is not in the range MIN_RADIX ≤ radix ≤ MAX_RADIX or if the value of ch is not a valid digit in the specified radix, -1 is returned. A character is a valid digit if at least one of the following is true:

      • The method isDigit is true of the character and the Unicode decimal digit value of the character (or its single-character decomposition) is less than the specified radix. In this case the decimal digit value is returned.
      • The character is one of the uppercase Latin letters 'A' through 'Z' and its code is less than radix + 'A' - 10. In this case, ch - 'A' + 10 is returned.
      • The character is one of the lowercase Latin letters 'a' through 'z' and its code is less than radix + 'a' - 10. In this case, ch - 'a' + 10 is returned.
      • The character is one of the fullwidth uppercase Latin letters A ('\uFF21') through Z ('\uFF3A') and its code is less than radix + '\uFF21' - 10. In this case, ch - '\uFF21' + 10 is returned.
      • The character is one of the fullwidth lowercase Latin letters a ('\uFF41') through z ('\uFF5A') and its code is less than radix + '\uFF41' - 10. In this case, ch - '\uFF41' + 10 is returned.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the digit(int, int) method.

      Parameters:
      ch - the character to be converted.
      radix - the radix.
      Returns:
      the numeric value represented by the character in the specified radix.
      See Also:

    • digit

      public static int digit(int codePoint, int radix)
      Returns the numeric value of the specified character (Unicode code point) in the specified radix.

      If the radix is not in the range MIN_RADIX ≤ radix ≤ MAX_RADIX or if the character is not a valid digit in the specified radix, -1 is returned. A character is a valid digit if at least one of the following is true:

      • The method isDigit(codePoint) is true of the character and the Unicode decimal digit value of the character (or its single-character decomposition) is less than the specified radix. In this case the decimal digit value is returned.
      • The character is one of the uppercase Latin letters 'A' through 'Z' and its code is less than radix + 'A' - 10. In this case, codePoint - 'A' + 10 is returned.
      • The character is one of the lowercase Latin letters 'a' through 'z' and its code is less than radix + 'a' - 10. In this case, codePoint - 'a' + 10 is returned.
      • The character is one of the fullwidth uppercase Latin letters A ('\uFF21') through Z ('\uFF3A') and its code is less than radix + '\uFF21' - 10. In this case, codePoint - '\uFF21' + 10 is returned.
      • The character is one of the fullwidth lowercase Latin letters a ('\uFF41') through z ('\uFF5A') and its code is less than radix + '\uFF41'- 10. In this case, codePoint - '\uFF41' + 10 is returned.
      Parameters:
      codePoint - the character (Unicode code point) to be converted.
      radix - the radix.
      Returns:
      the numeric value represented by the character in the specified radix.
      Since:
      1.5
      See Also:

    • getNumericValue

      public static int getNumericValue(char ch)
      Returns the int value that the specified Unicode character represents. For example, the character '\u216C' (the roman numeral fifty) will return an int with a value of 50.

      The letters A-Z in their uppercase ('\u0041' through '\u005A'), lowercase ('\u0061' through '\u007A'), and full width variant ('\uFF21' through '\uFF3A' and '\uFF41' through '\uFF5A') forms have numeric values from 10 through 35. This is independent of the Unicode specification, which does not assign numeric values to these char values.

      If the character does not have a numeric value, then -1 is returned. If the character has a numeric value that cannot be represented as a nonnegative integer (for example, a fractional value), then -2 is returned.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the getNumericValue(int) method.

      Parameters:
      ch - the character to be converted.
      Returns:
      the numeric value of the character, as a nonnegative int value; -2 if the character has a numeric value but the value can not be represented as a nonnegative int value; -1 if the character has no numeric value.
      Since:
      1.1
      See Also:

    • getNumericValue

      public static int getNumericValue(int codePoint)
      Returns the int value that the specified character (Unicode code point) represents. For example, the character '\u216C' (the Roman numeral fifty) will return an int with a value of 50.

      The letters A-Z in their uppercase ('\u0041' through '\u005A'), lowercase ('\u0061' through '\u007A'), and full width variant ('\uFF21' through '\uFF3A' and '\uFF41' through '\uFF5A') forms have numeric values from 10 through 35. This is independent of the Unicode specification, which does not assign numeric values to these char values.

      If the character does not have a numeric value, then -1 is returned. If the character has a numeric value that cannot be represented as a nonnegative integer (for example, a fractional value), then -2 is returned.

      Parameters:
      codePoint - the character (Unicode code point) to be converted.
      Returns:
      the numeric value of the character, as a nonnegative int value; -2 if the character has a numeric value but the value can not be represented as a nonnegative int value; -1 if the character has no numeric value.
      Since:
      1.5
      See Also:

    • isSpace

      @Deprecated(since="1.1") public static boolean isSpace(char ch)
      Deprecated.
      Replaced by isWhitespace(char).
      Determines if the specified character is ISO-LATIN-1 white space. This method returns true for the following five characters only:
      truechars
      Character Code Name
      '\t' U+0009 HORIZONTAL TABULATION
      '\n' U+000A NEW LINE
      '\f' U+000C FORM FEED
      '\r' U+000D CARRIAGE RETURN
      ' ' U+0020 SPACE
      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is ISO-LATIN-1 white space; false otherwise.
      See Also:

    • isSpaceChar

      public static boolean isSpaceChar(char ch)
      Determines if the specified character is a Unicode space character. A character is considered to be a space character if and only if it is specified to be a space character by the Unicode Standard. This method returns true if the character's general category type is any of the following:
      • SPACE_SEPARATOR
      • LINE_SEPARATOR
      • PARAGRAPH_SEPARATOR

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isSpaceChar(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is a space character; false otherwise.
      Since:
      1.1
      See Also:

    • isSpaceChar

      public static boolean isSpaceChar(int codePoint)
      Determines if the specified character (Unicode code point) is a Unicode space character. A character is considered to be a space character if and only if it is specified to be a space character by the Unicode Standard. This method returns true if the character's general category type is any of the following:
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is a space character; false otherwise.
      Since:
      1.5
      See Also:

    • isWhitespace

      public static boolean isWhitespace(char ch)
      Determines if the specified character is white space according to Java. A character is a Java whitespace character if and only if it satisfies one of the following criteria:
      • It is a Unicode space character (SPACE_SEPARATOR, LINE_SEPARATOR, or PARAGRAPH_SEPARATOR) but is not also a non-breaking space ('\u00A0', '\u2007', '\u202F').
      • It is '\t', U+0009 HORIZONTAL TABULATION.
      • It is '\n', U+000A LINE FEED.
      • It is '\u000B', U+000B VERTICAL TABULATION.
      • It is '\f', U+000C FORM FEED.
      • It is '\r', U+000D CARRIAGE RETURN.
      • It is '\u001C', U+001C FILE SEPARATOR.
      • It is '\u001D', U+001D GROUP SEPARATOR.
      • It is '\u001E', U+001E RECORD SEPARATOR.
      • It is '\u001F', U+001F UNIT SEPARATOR.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isWhitespace(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is a Java whitespace character; false otherwise.
      Since:
      1.1
      See Also:

    • isWhitespace

      public static boolean isWhitespace(int codePoint)
      Determines if the specified character (Unicode code point) is white space according to Java. A character is a Java whitespace character if and only if it satisfies one of the following criteria:
      • It is a Unicode space character (SPACE_SEPARATOR, LINE_SEPARATOR, or PARAGRAPH_SEPARATOR) but is not also a non-breaking space ('\u00A0', '\u2007', '\u202F').
      • It is '\t', U+0009 HORIZONTAL TABULATION.
      • It is '\n', U+000A LINE FEED.
      • It is '\u000B', U+000B VERTICAL TABULATION.
      • It is '\f', U+000C FORM FEED.
      • It is '\r', U+000D CARRIAGE RETURN.
      • It is '\u001C', U+001C FILE SEPARATOR.
      • It is '\u001D', U+001D GROUP SEPARATOR.
      • It is '\u001E', U+001E RECORD SEPARATOR.
      • It is '\u001F', U+001F UNIT SEPARATOR.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is a Java whitespace character; false otherwise.
      Since:
      1.5
      See Also:

    • isISOControl

      public static boolean isISOControl(char ch)
      Determines if the specified character is an ISO control character. A character is considered to be an ISO control character if its code is in the range '\u0000' through '\u001F' or in the range '\u007F' through '\u009F'.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isISOControl(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      true if the character is an ISO control character; false otherwise.
      Since:
      1.1
      See Also:

    • isISOControl

      public static boolean isISOControl(int codePoint)
      Determines if the referenced character (Unicode code point) is an ISO control character. A character is considered to be an ISO control character if its code is in the range '\u0000' through '\u001F' or in the range '\u007F' through '\u009F'.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is an ISO control character; false otherwise.
      Since:
      1.5
      See Also:

    • getType

      public static int getType(char ch)
      Returns a value indicating a character's general category.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the getType(int) method.

      Parameters:
      ch - the character to be tested.
      Returns:
      a value of type int representing the character's general category.
      Since:
      1.1
      See Also:

    • getType

      public static int getType(int codePoint)
      Returns a value indicating a character's general category.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      a value of type int representing the character's general category.
      Since:
      1.5
      See Also:

    • forDigit

      public static char forDigit(int digit, int radix)
      Determines the character representation for a specific digit in the specified radix. If the value of radix is not a valid radix, or the value of digit is not a valid digit in the specified radix, the null character ('\u0000') is returned.

      The radix argument is valid if it is greater than or equal to MIN_RADIX and less than or equal to MAX_RADIX. The digit argument is valid if 0 <= digit < radix.

      If the digit is less than 10, then '0' + digit is returned. Otherwise, the value 'a' + digit - 10 is returned.

      Parameters:
      digit - the number to convert to a character.
      radix - the radix.
      Returns:
      the char representation of the specified digit in the specified radix.
      See Also:

    • getDirectionality

      public static byte getDirectionality(char ch)
      Returns the Unicode directionality property for the given character. Character directionality is used to calculate the visual ordering of text. The directionality value of undefined char values is DIRECTIONALITY_UNDEFINED.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the getDirectionality(int) method.

      Parameters:
      ch - char for which the directionality property is requested.
      Returns:
      the directionality property of the char value.
      Since:
      1.4
      See Also:

    • getDirectionality

      public static byte getDirectionality(int codePoint)
      Returns the Unicode directionality property for the given character (Unicode code point). Character directionality is used to calculate the visual ordering of text. The directionality value of undefined character is DIRECTIONALITY_UNDEFINED.
      Parameters:
      codePoint - the character (Unicode code point) for which the directionality property is requested.
      Returns:
      the directionality property of the character.
      Since:
      1.5
      See Also:

    • isMirrored

      public static boolean isMirrored(char ch)
      Determines whether the character is mirrored according to the Unicode specification. Mirrored characters should have their glyphs horizontally mirrored when displayed in text that is right-to-left. For example, '\u0028' LEFT PARENTHESIS is semantically defined to be an opening parenthesis. This will appear as a "(" in text that is left-to-right but as a ")" in text that is right-to-left.

      Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isMirrored(int) method.

      Parameters:
      ch - char for which the mirrored property is requested
      Returns:
      true if the char is mirrored, false if the char is not mirrored or is not defined.
      Since:
      1.4

    • isMirrored

      public static boolean isMirrored(int codePoint)
      Determines whether the specified character (Unicode code point) is mirrored according to the Unicode specification. Mirrored characters should have their glyphs horizontally mirrored when displayed in text that is right-to-left. For example, '\u0028' LEFT PARENTHESIS is semantically defined to be an opening parenthesis. This will appear as a "(" in text that is left-to-right but as a ")" in text that is right-to-left.
      Parameters:
      codePoint - the character (Unicode code point) to be tested.
      Returns:
      true if the character is mirrored, false if the character is not mirrored or is not defined.
      Since:
      1.5

    • compareTo

      public int compareTo(Character anotherCharacter)
      Compares two Character objects numerically.
      Specified by:
      compareTo in interface Comparable<Character>
      Parameters:
      anotherCharacter - the Character to be compared.
      Returns:
      the value 0 if the argument Character is equal to this Character; a value less than 0 if this Character is numerically less than the Character argument; and a value greater than 0 if this Character is numerically greater than the Character argument (unsigned comparison). Note that this is strictly a numerical comparison; it is not locale-dependent.
      Since:
      1.2

    • compare

      public static int compare(char x, char y)
      Compares two char values numerically. The value returned is identical to what would be returned by: 
          Character.valueOf(x).compareTo(Character.valueOf(y))
      Parameters:
      x - the first char to compare
      y - the second char 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

    • reverseBytes

      public static char reverseBytes(char ch)
      Returns the value obtained by reversing the order of the bytes in the specified char value.
      Parameters:
      ch - The char of which to reverse the byte order.
      Returns:
      the value obtained by reversing (or, equivalently, swapping) the bytes in the specified char value.
      Since:
      1.5

    • getName

      public static String getName(int codePoint)
      Returns the name of the specified character codePoint, or null if the code point is unassigned.

      If the specified character is not assigned a name by the UnicodeData file (part of the Unicode Character Database maintained by the Unicode Consortium), the returned name is the same as the result of the expression:

      Character.UnicodeBlock.of(codePoint).toString().replace('_', ' ') + " " + Integer.toHexString(codePoint).toUpperCase(Locale.ROOT);
      For the codePoints in the UnicodeData file, the name returned by this method follows the naming scheme in the "Unicode Name Property" section of the Unicode Standard. For other code points, such as Hangul/Ideographs, The name generation rule above differs from the one defined in the Unicode Standard.
      Parameters:
      codePoint - the character (Unicode code point)
      Returns:
      the name of the specified character, or null if the code point is unassigned.
      Throws:
      IllegalArgumentException - if the specified codePoint is not a valid Unicode code point.
      Since:
      1.7

    • codePointOf

      public static int codePointOf(String name)
      Returns the code point value of the Unicode character specified by the given character name.

      If a character is not assigned a name by the UnicodeData file (part of the Unicode Character Database maintained by the Unicode Consortium), its name is defined as the result of the expression:

      Character.UnicodeBlock.of(codePoint).toString().replace('_', ' ') + " " + Integer.toHexString(codePoint).toUpperCase(Locale.ROOT);

      The name matching is case insensitive, with any leading and trailing whitespace character removed. For the code points in the UnicodeData file, this method recognizes the name which conforms to the name defined in the "Unicode Name Property" section in the Unicode Standard. For other code points, this method recognizes the name generated with getName(int) method.

      Parameters:
      name - the character name
      Returns:
      the code point value of the character specified by its name.
      Throws:
      IllegalArgumentException - if the specified name is not a valid character name.
      NullPointerException - if name is null
      Since:
      9