Java basic grammar-identifier naming convention

Constituent elements

1. Alphabet: a-zA-Z

2. Numbers: 0-9

3. Symbol: underscore _, dollar sign $ (bold)

Identifier rules

1. Number cannot start
2. Keywords cannot be used
3. Strictly case-sensitive, when naming names are not limited in length, try to be as clear as possible

note:

1. The name of the class: Capitalize the first letter of each word, capitalize the first letter of each word;
2. The name of the method: the first letter is lowercase, and the first letter of each word is uppercase; (camel case nomenclature)