Java Character isUnicodeIdentifierStart(int codePoint) Method

Java isUnicodeIdentifierStart(int codePoint) is a part of Character class. This method is used to check whether the specified Unicode codepoint character is allowed as the first character in a Unicode identifier or not.

This method also supports supplementary characters. A character may start a Unicode identifier if and only if one of the following conditions is true:

  • isLetter(ch) returns true
  • getType(ch) returns LETTER_NUMBER.

Syntax:

public static boolean isUnicodeIdentifierStart(int codePoint)

Parameters:

The parameter passed is the Unicode codepoint character to be checked whether it is allowed as a start character in the Unicode identifier.

Returns:

Returns the boolean value true if the specified Unicode codepoint character is allowed as the first character of Unicode identifier else return false.

Example 1:

Here, the characters are checked whether they are allowed as start character of Unicode identifier or not.

public class StudyTonight
{  
	public static void main(String[] args)
	{  
		int cp1 = 32;  
		int cp2 = 60;  
		int cp3 = 119;  
		int cp4 = 93;   
		int cp5 = 1232;  

		boolean b1 = Character.isUnicodeIdentifierStart(cp1);  
		boolean b2 = Character.isUnicodeIdentifierStart(cp2);  
		boolean b3 = Character.isUnicodeIdentifierStart(cp3);  
		boolean b4 = Character.isUnicodeIdentifierStart(cp4);  
		boolean b5 = Character.isUnicodeIdentifierStart(cp5);  

		System.out.println((char)cp1 +" is a start Unicode identifier??::  "+b1);  
		System.out.println((char)cp2 +" is a start Unicode identifier??::  "+b2);  
		System.out.println((char)cp3 +" is a start Unicode identifier??::  "+b3);  
		System.out.println((char)cp4 +" is a start Unicode identifier??::  "+b4);  
		System.out.println((char)cp5 +" is a start Unicode identifier??::  "+b5);  
	}  
} 


is a start Unicode identifier??:: false
< is a start Unicode identifier??:: false
w is a start Unicode identifier??:: true
] is a start Unicode identifier??:: false
? is a start Unicode identifier??:: true

Example 2:

Here is a user-defined example where anyone using this code can put a value of his choice and get the equivalent output.

import java.util.Scanner; 
public class StudyTonight
{  
	public static void main(String[] args)
	{  
		try
		{
			System.out.print("Enter the Unicode character: ");  
			Scanner sc = new Scanner(System.in);        
			int cp = sc.nextInt(); 
			boolean b = Character.isUnicodeIdentifierStart(cp);
			System.out.println((char)cp + " is a start Unicode identifier??: "+b);
		}
		catch(Exception e)
		{
			System.out.println("Invalid Input!!");
		}
	}
}


Enter the Unicode character: 67
C is a start Unicode identifier??: true
*******************************************
Enter the Unicode character: 55
7 is a start Unicode identifier??: false

Live Example:

Here, you can test the live code example. You can execute the example for different values, even can edit and write your examples to test the Java code.