Character Wrapper Class

Java provides two main ways to work with characters:

• char → primitive type

• Character → wrapper class

Useful Character Methods

isLetter()

Checks whether a character is a letter.

System.out.println(Character.isLetter('A')); // true
System.out.println(Character.isLetter('5')); // false

isDigit()

Checks whether a character is a digit.

System.out.println(Character.isDigit('5')); // true
System.out.println(Character.isDigit('A')); // false

isWhitespace()

Checks for whitespace.

System.out.println(Character.isWhitespace(' '));  // true
System.out.println(Character.isWhitespace('A'));  // false

isUpperCase()

System.out.println(Character.isUpperCase('A')); // true
System.out.println(Character.isUpperCase('a')); // false

isLowerCase()

System.out.println(Character.isLowerCase('a')); // true
System.out.println(Character.isLowerCase('A')); // false

toUpperCase()

Converts a character to uppercase.

char ch = Character.toUpperCase('a');

System.out.println(ch);

Output:

A

toLowerCase()

Converts a character to lowercase.

char ch = Character.toLowerCase('A');

System.out.println(ch);

Output:

a

toString()

Converts a character into a String.

String str = Character.toString('A');

System.out.println(str);

Output:

A

4. Unicode

Java uses Unicode to represent characters.

A char is 16 bits and can represent characters from:

U+0000 → U+FFFF

This range is called the Basic Multilingual Plane (BMP).

Some Unicode characters are outside this range and require two char values (a surrogate pair).

For most normal character operations, you can simply use:

char ch = 'A';

5. Escape Sequences

Escape sequences start with \ and represent special characters.

Example:

System.out.println("She said \"Hello!\"");

Output:

She said "Hello!"