Java.lang.Character.isUnicodeIdentifierStart() Method

Description

The java.lang.Character.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:

• isLetter(ch) returns true

• getType(ch) returns LETTER_NUMBER.

Declaration

Following is the declaration for java.lang.Character.isUnicodeIdentifierStart() method

public static boolean isUnicodeIdentifierStart(char ch)

Parameters

• ch - the character to be tested

Return Value

This method returns true if the character may start a Unicode identifier, false otherwise.

Exception

• NA

Example

The following example shows the usage of lang.Character.isUnicodeIdentifierStart() method.

package com.tutorialspoint;

import java.lang.*;

public class CharacterDemo {

   public static void main(String[] args) {

      // create 2 char primitives ch1, ch2
      char ch1, ch2;

      // assign values to ch1, ch2
      ch1 = '_';
      ch2 = 'p';

      // create 2 boolean primitives b1, b2
      boolean b1, b2;

      /**
       *  check if ch1, ch2 may start a Unicode identifier 
       *  and assign results to b1, b2
       */
      b1 = Character.isUnicodeIdentifierStart(ch1);
      b2 = Character.isUnicodeIdentifierStart(ch2);

      String str1 = ch1 + " may start a Unicode identifier is " + b1;
      String str2 = ch2 + " may start a Unicode identifier is " + b2;

      // print b1, b2 values
      System.out.println( str1 );
      System.out.println( str2 );
   }
}

Let us compile and run the above program, this will produce the following result:

_ may start a Unicode identifier is false
p may start a Unicode identifier is true