Java.lang.Character.isIdentifierIgnorable() Method



The java.lang.Character.isIdentifierIgnorable(char ch) determines if the specified character should be regarded as an ignorable character in a Java identifier or a Unicode identifier.

The following Unicode characters are ignorable in a Java identifier or a Unicode identifier −

  • ISO control characters that are not whitespace

    • '\u0000' through '\u0008'
    • '\u000E' through '\u001B'
    • '\u007F' through '\u009F'
  • all characters that have the FORMAT general category value


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

public static boolean isIdentifierIgnorable(char ch)


ch − the character to be tested

Return Value

This method returns true if the character is an ignorable control character that may be part of a Java or Unicode identifier, false otherwise.




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

package com.tutorialspoint;

import java.lang.*;

public class CharacterDemo {

   public static void main(String[] args) {

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

      // assign values to ch1, ch2
      ch1 = '\u0000';
      ch2 = '8';

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

      // assign isIdentifierIgnorable results of ch1, ch2 to b1, b2
      b1 = Character.isIdentifierIgnorable(ch1);
      b2 = Character.isIdentifierIgnorable(ch2);

      String str1 = "ch1 is an ignorable control character is " + b1;
      String str2 = "ch2 is an ignorable control character 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 −

ch1 is an ignorable control character is true
ch2 is an ignorable control character is false