Java Learning Note Two--identifiers and keywords

Identifier definition

Definition of identifiers: The sequence of characters used to name features such as various variables, methods, and classes becomes an identifier.

Simply put, the name of the place where you can call the identifier, the rules of the identifier must abide by.

Naming rules

1. Identifiers can only consist of letters, underscores "_", Dollar Signs "$", or numbers
2. Identifiers can only start with a letter, underscore, or dollar symbol
3. Identifiers cannot be Java keywords and reserved words
4. Identifier case sensitive, unlimited length

Conventional

In order for Java code to be better maintained and aesthetically pleasing, it is common to write Java code that follows some established rules:

• Identifiers may be made up of a number of words or abbreviations, but the name cannot be too long
• When a word consists of multiple words, the first letter is lowercase, and the other words are capitalized in a mixed case, such as: UserName.
• Class name capitalized, other (variable name, method name, etc.) First letter lowercase

Key words

Keywords are strings in Java that are assigned specific meanings and are used for specialized purposes. All Java keywords are in lowercase english.

Goto and const, although never used, are also reserved as Java keywords

All keywords are as follows:

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

Java Learning Note Two--identifiers and keywords