Java - Character isIdentifierIgnorable() Method

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The Java Character isIdentifierIgnorable() method determines if the specified character should be regarded as an ignorable character in either 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 whitespaces: '\u0000' through '\u0008', '\u000E' through '\u001B', '\u007F' through '\u009F'

• All characters that have the FORMAT general category value

Note − This method occurs in two polymorphic forms: one takes a character value parameter while the other takes an integer code point parameter.

Syntax

Following is the syntax for Java Character isIdentifierIgnorable() method

public static boolean isIdentifierIgnorable(char ch)
(or)
public static boolean isIdentifierIgnorable(int codePoint)

Parameters

• ch − the character to be tested

• codePoint − the Unicode code point to be tested

Return Value

This method returns true if the character is an ignorable control character belonging to either Java or Unicode identifiers, otherwise false.

Example

The following example shows the usage of Java Character isIdentifierIgnorable(char ch) 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 );
   }
}

Output

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

Example

The following example shows the usage of Java Character isIdentifierIgnorable(int codePoint) method.

package com.tutorialspoint;
import java.lang.*;
public class CharacterDemo {
   public static void main(String[] args) {

      // create 2 int primitives cp1, cp2
      int cp1, cp2;

      // assign values to cp1, cp2
      cp1 = 0x008f;
      cp2 = 0x0abc;

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

      // assign isIdentifierIgnorable results of cp1, cp2 to b1, b2
      b1 = Character.isIdentifierIgnorable(cp1);
      b2 = Character.isIdentifierIgnorable(cp2);
      String str1 = "cp1 is an ignorable control character is "+b1;
      String str2 = "cp2 is an ignorable control character is "+b2;

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

Output

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

cp1 is an ignorable control character is true
cp2 is an ignorable control character is false

Example

As the method returns boolean values, we can use it as a condition to a conditional statement.

In the following example, we are passing a char value as the argument to this method. The return value of this method is used as a condition to the if-else statement.

import java.lang.*;
public class Demo {
   public static void main(String[] args) {
      char ch1 = '\u0db3';
      if(Character.isIdentifierIgnorable(ch1))
         System.out.println("The character is ignorable");
      else
         System.out.println("The character is not ignorable");
   }
}

Output

If we compile and run the method, the output is printed as follows −

The character is not ignorable

Example

Let us now pass ignorable characters as arguments to this method in the following example.

import java.lang.*;
public class Demo {
   public static void main(String[] args) {
      char ch1 = '\u0001';
      if(Character.isIdentifierIgnorable(ch1))
         System.out.println("The character is ignorable");
      else
         System.out.println("The character is not ignorable");
   }
}

Output

The output is displayed as follows −

The character is ignorable