Identifiers are used to name elements of Java programs, such as classes, interfaces, variables, methods, constructors, and arguments.
A valid name begins with a Unicode letter, underscore character (_), or dollar sign ($).
A Unicode letter is an English letter (a-z) or (A-Z) or a letter in a non-English language.
The second and remaining letters of an identifier may be a Unicode letter, underscore, dollar sign, or digit (0-9).
The dollar sign character is used by compiler-internal identifiers and should be avoided.
Identifiers are case sensitive. The identifiers myID and MyID are considered
to be separate identifiers.
An identifier may not use the literal values, true, false, null, or any of the keywords that are reserved by Java.
The Java language reserves a list of 53 keywords.
Keywords may not be used as Java variables.
Click the Quiz link below to check your understanding of the main() method, identifiers, and keywords.
Keyword Identifier - Quiz