What is Java identifier ?

In Java, an identifier is a fancy name for a custom label you give to things like variables, methods, classes, and even labels within your code. These labels are critical for differentiating between different parts of your program and and and and making your code readable.

Here's what makes a valid Java identifier:

Characters: Identifiers can only contain letters (uppercase and lowercase), digits (0-9), the dollar sign ($), and the underscore (_).

Starting character: The first character of an identifier must be a letter or one of the special characters ($ or _). Digits cannot be the first character.

Case sensitivity: Java identifiers are case-sensitive. This means that myVariable and MyVariable are considered different identifiers.

No keywords: You cannot use reserved keywords (like int, for, if, etc.) as identifiers.

Here are some examples of valid Java identifiers:

name

customerAge

total_cost

$temporaryValue (using dollar sign)

And some examples of invalid identifiers:

1stPlace (cannot start with a number)

if (reserved keyword)

my-variable (hyphens are not allowed)

By following these rules, you can create clear and meaningful identifiers that improve the readability and maintainability of your Java code.