Identifier IN JAVA

Idenifiers:

Any Name in Java which is used for identifing Purpose is called as Identifier..

Ex:- className,VariableName,Method name,Constructor Name are Identifiers.

Rules for Identifiers:

1. Identifiers Can have alphanumeric Values and $ and _.

2. Identifiers can not start from Numbers..

3. Identifiers are Case sensitive.

4. There is no length Limit in Identifiers.

5. Pre-defined Keywords cant be used as an Identifiers.

6. Pre-defined Classname,Methodname,Interface Name,variable Name etc can be used as an Identifiers.

Recommendation:

1.

Pre-defined Classname,Methodname,Interface Name,variable Name etc should not be used as an Identifiers because it creates confusion.

CASE STUDY:

class Test

{

public static void main (String [] beast)

{

System.out.println("Test in progress");

int System=10;

System.out.println(a);

}

}

OUTPUT:

Compilation Error:

test.java:9: error: cannot find symbol

System.out.println(a);

^

symbol: variable a

location: class Test

test.java:9: error: int cannot be dereferenced

System.out.println(a);

Explanation:

Because System is Predefined Class name.It can be used as an identifier but then we cant use it is as Class Name identifier...