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0004 Keywords and Identifiers

A keyword is a word whose meaning is defined by the programming language. Java Keywords and Reserved Words: abstract class extends implements null strictfp true assert const false import package super try boolean continue final instanceof private switch void break default finally int protected synchronized volatile byte do float interface public this while case double for long return throw catch else goto native short throws char enum if new static transient An identifier is a word used by a programmer to name a variable, method, class, or label. Keywords and reserved words may not be used as identifiers. An identifier must begin with a letter, a dollar sign ($), or an underscore (_); subsequent characters may be letters, dollar signs, underscores, or digits. Some examples are: foobar // legal Myclass // legal $a // legal 3_a // illegal: starts with a digit !theValue // illegal: bad 1st char Identifiers are case sensitive. For example, myValue and MyValue are distinct identifiers.