what is java identifier

In the Java language, an identifier is a string starting with a letter, underscore (_) or dollar sign ($) and consisting of letters, numbers, underscore (_) or dollar sign ($). Identifiers are case-sensitive and have no limit on length.

In Java, we need to identify many elements of the code, including class names, methods , fields, variables, package names, etc. The name we choose is called an identifier and follows the following rules: (Recommended learning: java course )

(1) The identifier cannot be a keyword or true, false, null.

(2) Identifiers can contain letters, numbers 0-9, underscores (_), or dollar signs ($).

(3) The first character of the identifier must be a letter, underscore (_) or dollar sign ($).

(4) Identifiers are case-sensitive and have no maximum length specified.

Examples of legal identifiers: age, $salary, _value, __1_value Examples of illegal identifiers: 123abc, -salary

It is best to name the identifier to reflect its function and be visible. Know it

For example: The following identifier is legal:

myName，My_name，Points，$points,_sys_ta，OK，_23b，_3_，Myvoid

The following identifier is illegal:

#name，25name，class，&time，if

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