One of the basics of Java: Naming rules (package name, class name, variable name, method name)

1. Package Name: Package name is usually lowercase English letter

2. Class Name: Capitalize the first letter of the word

3. Variable Name:

1) identifiers consist of letters, numbers, underscores "_", dollar Sign "$" or the renminbi symbol "￥", and the initial letter cannot be a number.
2) Keywords and reserved words cannot be identified as identifiers.
3) identifiers do not have a length limit.
4) The identifier is case sensitive.

4, Method name: First word lowercase, after the first letter of the word capital

Note that the default byte storage for different variable types. Java decimal is the default double type, such as above (float) 4.5, if you write 4.5 directly, will be in the place of 4.5 red wavy line, indicating that this place is wrong.

One of the basics of Java: Naming rules (package name, class name, variable name, method name)