Java learns from zero (identifiers and keywords)

identifiers, keywords, commentsFirst, identifiers

The names of packages, classes, methods, parameters, and variables in Java consist of any order of size letters, numbers, underscores (_), and dollar signs ($).

Identifier: Cannot start with a number and cannot be a reserved keyword in Java

such as: Yourname, Yourname_dxh, Li_yourname, $yourname are legal identifiers

Class, 67.9,hello World is not legal, class is the keyword, 67.9 starts with a number, there is a space in the middle of Hello world

Second, the key word

Keywords in Java

Abstract	Boolean	Break	Byte	Case	Catch	Char
Class	Continue	Default	Do	Double	Else	Extends
False	Final	Finally	Float	For	If	Implements
Import	instanceof	Int	Interface	Long	Native	New
Null	Package	Private	Protected	Public	Return	Short
Static	Synchronized	Super	This	Throw	Throws	Transient
True	Try	void	Volatile	While	Assert	Enum

Third, comments

• Single-line Comment:

// represents a single-line comment, where the comment is in the comment line, preceded by a double slash (//) before the content needs to be commented

• Multi-line Comments:

/* * Multiline comment, beginning with a single slash plus a Star (/*), ending with a single slash (*/) in the star */

• Document comments

/** * Document Comments * Preceded by a single slash plus two star marks (/**), with a star marker and a slash (*/) End * The content of this method annotation will be interpreted as the official document of the program, And can be included ina document generated by tools such as: Javadoc * * *

Java learns from zero (identifiers and keywords)