Character

Character Wrapper Class in Java

Overview

The Character wrapper class in Java allows the use of a char value as an object. It belongs to the java.lang package and is useful for working with methods that require objects or when performing utility operations on characters.

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Characteristics of Character Wrapper Class

Feature	Details
Package	java.lang
Default Value	\u0000 (null character)
Immutable	Character objects are immutable.

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Key Features of the Character Class

• Immutability: Character objects are immutable, meaning their value cannot be changed once created.
• Utility Methods: Includes static methods to classify, convert, and inspect characters.

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Static Methods

Method	Description	Return Type	Example
isDigit(char ch)	Determines if the specified character is a digit.	boolean	Character.isDigit('5'); // true
isLetter(char ch)	Determines if the specified character is a letter.	boolean	Character.isLetter('A'); // true
isLetterOrDigit(char ch)	Determines if the specified character is a letter or digit.	boolean	Character.isLetterOrDigit('9'); // true
isLowerCase(char ch)	Determines if the specified character is lowercase.	boolean	Character.isLowerCase('a'); // true
isUpperCase(char ch)	Determines if the specified character is uppercase.	boolean	Character.isUpperCase('Z'); // true
isWhitespace(char ch)	Determines if the specified character is a whitespace character.	boolean	Character.isWhitespace(' '); // true
isSpaceChar(char ch)	Determines if the specified character is a space character.	boolean	Character.isSpaceChar(' '); // true
toString(char c)	Returns a String object representing the specified character.	String	Character.toString('A'); // "A"
getNumericValue(char ch)	Returns the numeric value of the specified character.	int	Character.getNumericValue('7'); // 7
getType(char ch)	Returns the general category type of the specified character.	int	Character.getType('A'); // 1
forDigit(int digit, int radix)	Returns the character representation of the specified digit in the specified radix.	char	Character.forDigit(10, 16); // 'a'
isDefined(char ch)	Determines if the specified character is defined in Unicode.	boolean	Character.isDefined('©'); // true
isTitleCase(char ch)	Determines if the specified character is a titlecase character.	boolean	Character.isTitleCase('Dž'); // true
toLowerCase(char ch)	Converts the specified character to lowercase.	char	Character.toLowerCase('A'); // 'a'
toUpperCase(char ch)	Converts the specified character to uppercase.	char	Character.toUpperCase('b'); // 'B'
toTitleCase(char ch)	Converts the specified character to titlecase.	char	Character.toTitleCase('Dž'); // 'Dž'
toChars(int codePoint)	Converts a Unicode code point to a char array.	char[]	Character.toChars(128512); // ['😀']

For more: Comprehensive List of Static Methods

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Instance Methods

Character value = 'A';

Method	Description	Return Type	Example
charValue()	Returns the primitive char value of this Character object.	char	value.charValue();
toString()	Returns a String representation of this Character.	String	value.toString();
equals(Object obj)	Compares this Character to another object.	boolean	value.equals('A');
hashCode()	Returns the hash code for this Character object.	int	value.hashCode();

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Arithmetic Operations

Although Character stores characters, it can participate in arithmetic operations because it is internally stored as an integer representing the Unicode value.

Operation	Symbol	Example
Increment	++	charValue++
Decrement	--	charValue--
Addition	+	'A' + 1 → 'B'
Subtraction	-	'C' - 1 → 'B'

Relational Operations

Operation	Symbol	Example
Equal to	==	'A' == 'A'
Not equal to	!=	'A' != 'B'
Greater than	>	'B' > 'A'
Less than	<	'A' < 'B'
Greater than or equal to	>=	'B' >= 'A'
Less than or equal to	<=	'A' <= 'B'

Relational Operators and Their Equivalent Methods

Character value1 = 'A';
Character value2 = 'B';

Operator	Operator Usage	Equivalent Method	Usage
==	value1 == value2; // false	equals(Object)	value1.equals(value2); // false
!=	value1 != value2; // true	!equals(Object)	!value1.equals(value2); // true
+	char sum = (char) (value1 + 1);	N/A	Operator only, but char arithmetic can be cast to maintain a range
<	value1 < value2; // true	compare(char, char)	Character.compare(value1, value2) < 0; // true
>	value1 > value2; // false	compare(char, char)	Character.compare(value1, value2) > 0; // false
<=	value1 <= value2; // true	compare(char, char)	Character.compare(value1, value2) <= 0; // true

Example Code

public class CharacterWrapperExample {
    public static void main(String[] args) {
        // Static Methods
        char c1 = 'A';
        char c2 = '5';

        // Check if a character is a digit
        boolean isDigit = Character.isDigit(c2); // true

        // Check if a character is a letter
        boolean isLetter = Character.isLetter(c1); // true

        // Convert a character to lowercase
        char lower = Character.toLowerCase(c1); // 'a'

        // Convert a character to uppercase
        char upper = Character.toUpperCase('b'); // 'B'

        // Check if a character is whitespace
        boolean isWhitespace = Character.isWhitespace(' '); // true

        // Get numeric value of a character
        int numericValue = Character.getNumericValue('7'); // 7

        // Instance Methods
        Character charObj = Character.valueOf('A');

        // Get primitive char value
        char primitiveChar = charObj.charValue(); // 'A'

        // Convert Character object to String
        String charAsString = charObj.toString(); // "A"

        // Compare Character objects
        boolean isEqual = charObj.equals('A'); // true
    }
}

For more: CharacterWrapperClass.java