what is identifier in java

What is a java identifier

An identifier is a sequence of characters that names a class, interface, method, variable, etc.

Identifier composition rules:

1, English upper and lower case letters

2, numbers

3, $ and _

Notes:

1. It cannot start with a number

2. It cannot be a keyword in java

3. Distinguish Case

Common naming rules:

A. Package: all lowercase

Single-level package: lowercase

Example:

liuyi,com

Multi-level packages: lowercase, separated by .

Example:

cn.itcast,com.baidu

B. Class or interface

One word: capitalize the first letter of each word

Example:

Student,Demo

Multiple words: capitalize the first letter of each word

Example:

HelloWorld,StudentName

C. Method or variable

One word: the first letter is lowercase

Example:

name,main

Multiple words: starting from the second word, The first letter of each word is capitalized

Example:

studentAge,showAllNames()

D.Constant

All capital letters

One word: capital

Example:

PI

Multiple words: capitalized and separated by _

Example:

STUDENT_MAX_AGE

Recommended tutorial: Java tutorial

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