java.lang.Character isDefined(char ch)


The Character.isDefined(char ch) java method determines if a character is defined in Unicode.

A character is defined if at least one of the following is true:

  • It has an entry in the UnicodeData file.
  • It has a value in a range defined by the UnicodeData file.

This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isDefined(int) method.

The isDefined(char ch) method of Character class is static thus it should be accessed statically which means the we would be calling this method in this format:

Character.isDefined(char ch)

Non static method is usually called by just declaring method_name(argument) however in this case since the method is static, it should be called by appending the class name as suffix. We will be encountering a compilation problem if we call the java isDefined() method non statically.

Method Syntax

public static boolean isDefined(char ch)

Method Argument

Data Type Parameter Description
char ch the character to be tested

Method Returns

The isDefined(char ch) method of Character class returns true if the character has a defined meaning in Unicode; false otherwise.


Requires Java 1.0.2 and up

Java Character isDefined(char ch) Example

Below is a simple java example on the usage of isDefined(char ch) method of Character class.


import java.util.Scanner;

 * This example source code demonstrates the use of 
 * isDefined(char ch) method of Character class.

public class CharacterIsDefinedCharExample {

	public static void main(String[] args) {

		// Ask for user input
		System.out.print("Enter a character:");
		// use scanner to get the user input
		Scanner s = new Scanner(;
		// get a single character
		char value = s.nextLine().toCharArray()[0];
		// close the scanner object
		// check if the user input is defined in Unicode
		boolean checkBool = Character.isDefined(value);
		// print result
			System.out.print("User input '"+value+"' is defined in Unicode");
			System.out.print("User input '"+value+"' is defined in Unicode");


Sample Output

Below is the sample output when you run the above example.

java Character isDefined(char ch) example output