"Java" java_05 identifiers and character sets

1. Identifiers

Used to name variables, classes, and methods. Attention:

　　The identifier that represents the class name begins with an uppercase letter. such as:man, GoodMan

　　the identifiers that represent methods and variables begin with lowercase letters, and the following descriptive words begin with uppercase. Green(),greencard ()

The Java identifiers have the following naming conventions:

<1> identifiers must begin with a letter, underscore _ , dollar symbol $

<2> The other part of the identifier can be a letter, an underscore "_", a dollar symbol "$" , and any combination of numbers

<3> Java identifiers are case sensitive and have unlimited length

<4> it can't be . keywords for Java

Valid identifiers:

int a = 3;

int _123 = 3;

int $12AA = 3;

int variable 1 = 55;

An illegal identifier:

int 1a = 3; Cannot start with a number

int a# = 3; Cannot contain special characters such as #

int int = 3; Cannot use keywords

JAVA does not use the ASCII character set used in the usual language , but rather a Standard international character set such as Unicode.

2. Character Set

Keywords / reserved words in 3.JAVA

The Java keyword is reserved for internal use by the Java language , such as class for defining classes. Keywords can also be called reserved words , they mean the same

Abstract	Assert	Boolean	Break	Byte	Case
Catch	char (character)	Class	Const	Continue	Default
Do	Double	Else	Extends	Final	Finally
Float	For	Goto	If	Implements	Import
instanceof	Int	Interface	Long	Native	New
Null	Package	Private	Protected	Public	Return
Short	Static	Strictfp	Super	Switch	Synchronized
This	Throw	Throws	Transient	Try	void
Volatile	While

Note: You cannot use a keyword as a variable name or a method name

　

"Java" java_05 identifiers and character sets