java.lang.Character isJavaIdentifierStart(char ch)
Description
A character may start a Java identifier if and only if one of the following conditions is true:
- isLetter(ch) returns true
- getType(ch) returns LETTER_NUMBER
- ch is a currency symbol (such as ‘$’)
- ch is a connecting punctuation character (such as ‘_’).
This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isJavaIdentifierStart(int) method.
The isJavaIdentifierStart(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.isJavaIdentifierStart(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 isJavaIdentifierStart() method non statically.
Method Syntax
public static boolean isJavaIdentifierStart(char ch)
Method Argument
| Data Type | Parameter | Description |
|---|---|---|
| char | ch | the character to be tested. |
Method Returns
The isJavaIdentifierStart(char ch) method of Character class returns true if the character may start a Java identifier; false otherwise.
Compatibility
Requires Java 1.1 and up
Java Character isJavaIdentifierStart(char ch) Example
Below is a simple java example on the usage of isJavaIdentifierStart(char ch) method of Character class.
package com.javatutorialhq.java.examples;
import java.util.Scanner;
/*
* This example source code demonstrates the use of
* isJavaIdentifierStart(char ch) method of Character class.
*/
public class CharacterIsJavaIdentifierStartCharExample {
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(System.in);
// get a single character
char value = s.nextLine().toCharArray()[0];
// close the scanner object
s.close();
/*
* check if the user input is permissible as
* the first character in a Java identifier
*/
boolean checkBool = Character.isJavaIdentifierStart(value);
// print result
if (checkBool) {
System.out.print("User input '" + value + "' is permissible as "
+ "the first character in a Java identifier");
} else {
System.out.print("User input '" + value + "' is not permissible as "
+ "the first character in a Java identifier");
}
}
}
Sample Output
Below is the sample output when you run the above example.
