Java Identifier

 Java Identifier 

These are the names the programmers choose. These names can be assigned to variables, methods, functions, classes, etc., to uniquely identify from a compiler. Java keywords can not be used as an identifier.

Rules for Java Identifier:

1. The first character of an identifier must be a letter, an underscore(_), or a dollar sign($).

2. The rest of the characters in the identifier can be a letter, underscore, dollar sign, or digit. Note that spaces are not allowed in identifiers.

3. Identifier cannot match any of Java's keywords.

4. Identifiers are case-sensitive. This means that age and Age are different identifiers.

Valid Identifiers:

int a;

int hi_java;

int value4;

int $height;

Invalid Identifiers:

int hi java;  // uses a space

int 4value;  //start with digit

int for;   // for is keyword

int #height;  //does not start with dollar sign

Program for identifiers.

public class Identifier{

public static void main(String args[]){

int a=10;

int hi_java=12;

int value4=15;

int $height=33;

System.out.println("result is="+a);

System.out.println("result is="+hi_java);

System.out.println("result is="+value4);

System.out.println("result is="+$height);

}

}

Let's discuss our program and find identifiers:-

Identifier // which is the class name 

main  // main is method name

int a=10;

int hi_java=12;

int value4=15;

int $height=33;

String // Predefined class name

args  // variable name