Character Class in Java - Methods | Set 2

In Java, the Character Class wraps the value of a primitive data type char into an object of datatype Character. This object contains a single field having the data type char. This class provides several methods regarding character manipulations, like converting them from lowercase to uppercase. Character Class is based on Unicode Standards to provide character information.

Features of Character Class:

The key features of the character class in Java are listed below:

• It wraps a primitive char value in an object.
• It checks character properties like mirroring and alphabetic status.
• It supports Unicode code point validation
• It also enables byte reversal for characters.
  

Example: Using the toUpperCase method of the Character class to transform the character to uppercase.

// Java program to use the UpperClass method of
// Character class to convert a character to upper case
import java.util.*; 
public class Geeks

{ 
	public static void main(String[] args) 
	{ 
		// Create a character
		char ch = 'g';

		// Convert the character to upper case
		char res = Character.toUpperCase(ch);

		// Print the result
		System.out.println("Upper case of '" + ch + "' is '" + res + "'");

	} 
} 

Upper case of 'g' is 'G'

Declaration of Character Class

The declaration of character class is listed below:

public final class Character extends Object implements Serializable, Comparable<Character>

Note: The Character class is final that's why it cannot be subclassed.

Java Character Methods

The table below demonstrates the character class methods.

Note: Refer to this article Character Class set 1 Methods for set 1 methods.

Now, we are going to discuss about each method one by one in detail:

1. toUpperCase(): This method converts the given character in the argument to its uppercase based on Unicode values.

Syntax:

public static char toUpperCase(char ch)

• Parameter: It takes single character ch which is converted to upper case.
• Return Type: This method returns character of the argumented character in the uppercase.

2. toLowerCase(): This method converts given character in argument to its Lower case based on Unicode values.

Syntax:

public static char toLowerCase(char ch)

• Parameter: This method takes a character(ch) to be converted to Lower case
• Return Type: This method returns the character in Lower case character of the argumented character.

3. isMirrored(): This method checks whether passed argument is mirrored or not, based on Unicode values. 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. e.g. : [ ] { } ( )

Syntax:

public static boolean isMirrored(char ch)

• Parameter: This method takes a character ch
• Return Type: This method returns a boolean value if char 'ch' is mirrored, else false.

Example: Java code explaining use of toUpperCase(), toLowerCase(), isMirrored() methods of Character Class.

// Java program explaining Character class methods 
// toUpperCase(), toLowerCase(), isMirrored() 
import java.lang.Character; 

public class Geeks
{ 
	public static void main(String[] args) 
	{ 
		Character g1 = Character.valueOf('g'); 
		Character g2 = Character.valueOf('O'); 
		
		// Use of toUpperCase() method 
		char chUpper = Character.toUpperCase(g1); 
		char chUpper1 = Character.toUpperCase(g2); 
  
		System.out.println("Upper value for g : "+ chUpper); 
		System.out.println("Upper value for O : "+ chUpper1); 
		System.out.println("");         
		  
		// Use of toLowerCase() method 
		char chLower = Character.toLowerCase(g1); 
		char chLower1 = Character.toLowerCase(g2); 
		System.out.println("Lower value for G : "+ chLower); 
		System.out.println("Lower value for O : "+ chLower1); 
		System.out.println(""); 
  
		// Use of isMirrored() method 
		Character g3 = Character.valueOf('-'); 
		Character g4 = Character.valueOf(')'); 
		Character g5 = Character.valueOf('{'); 
		Character g6 = Character.valueOf(']'); 
  
		boolean checkBool1 = Character.isMirrored(g3); 
		boolean checkBool2 = Character.isMirrored(g4); 
		boolean checkBool3 = Character.isMirrored(g5); 
		boolean checkBool4 = Character.isMirrored(g6); 
		  
		System.out.println("Checking - : "+ checkBool1); 
		System.out.println("Checking ) : "+ checkBool2); 
		System.out.println("Checking { : "+ checkBool3); 
		System.out.println("Checking ] : "+ checkBool4); 
	} 
} 

Upper value for g : G
Upper value for O : O

Lower value for G : g
Lower value for O : o

Checking - : false
Checking ) : true
Checking { : true
Checking ] : true

4. reverseBytes(): This method returns a character by reversing the order of bytes in the argumented character.

Syntax:

public static char reverseBytes(char ch)

• Parameter: This method takes a single parameter a char (ch) whose bytes need to be reverse.
• Return Type: This method returns a new char value with the reversed value of the given char.

5. isAlphabetic(int CodePoint): This method is used to check whether the specified Unicode codePoint represents an alphabetic character.

Syntax:

public static boolean isAlphabetic(int codePoint)

• Parameter: This method takes a single int value codePoint the unicode value need to check.
• Return Type: It returns a boolean true if the code point is alphabetic or return false.

Example: Java code demonstrates the use of isValidCodePoint(), reverseBytes(), isAlphabetic() methods.

// Java program explaining Character class methods 
// isValidCodePoint(), reverseBytes(), isAlphabetical() 
import java.lang.Character; 
public class Geeks
{ 
	public static void main(String[] args) 
	{ 
		// Use of reverseBytes() method 
		Character g1 = '&'; 
		Character g2 = '5'; 

		char chreverse = Character.reverseBytes(g1); 
		char chreverse1 = Character.reverseBytes(g2); 

		System.out.println("Reverse char for & : "+ chreverse); 
		System.out.println("Revrese char for 5 : "+ chreverse1); 
		System.out.println(); 

		// Use of isAlphabetical() method 
		int c1 = 101, c2 = 132; 
		boolean check1 = Character.isAlphabetic(c1); 
		boolean check2 = Character.isAlphabetic(c2); 
		System.out.println("Is Unicode 101 alphabetic : "+ check1); 
		System.out.println("Is Unicode 132 alphabetic : "+ check2); 
		System.out.println(); 

		// Use of isValidCodePoint() method 
		int c3 = 0x012343, c4 = 0x01344ffff; 
		boolean check4 = Character.isValidCodePoint(c4); 
		boolean check3 = Character.isValidCodePoint(c3); 
		System.out.println("Validity check : "+ check3); 
		System.out.println("Validity check : "+ check4); 
	} 
} 

Reverse char for & : ☀
Revrese char for 5 : 㔀

Is Unicode 101 alphabetic : true
Is Unicode 132 alphabetic : false

Validity check : true
Validity check : false