Java Identifiers
An identifier is a programmer-defined name for a variable,
constant, class, method, package, object, etc.. in a program.
A Java identifier is a sequence of:
Letters from A to Z uppercase and lowercase.
Digits 0 to 9
The
underscore
_ and the
dollar sign $
Any
Unicode character over 00C0
An identifier
cannot
begin with a digit, cannot contain any white space and cannot contain
any of the following special characters:
+ - * / = % & # ! ? ^ " ' ~ \ | < > ( ) [ ] { } : ; . ,
Java is case-sensitive: name and Name are different
identifiers.
Legal
Java identifiers are:
Age
name
_Price
$amount
gön
numberOfElements
Ilegal Java identifiers:
4num //begins with a digit
z# //contains a special character #
"Age" // contains a special character "
My name //contains a white
space
Java Reserved Words
The
reserved words are identifiers
that cannot be used as programmer-defined names. They are also called
Keywords
and are defined in the syntax of the language
The reserved words in Java are:
abstract
|
continue
|
for
|
new
|
switch
|
assert
|
default
|
goto
|
package
|
synchronized
|
boolean
|
do
|
if
|
private
|
this
|
break
|
double
|
implements
|
protected
|
throw
|
byte
|
else
|
import
|
public
|
throws
|
case
|
enum
|
instanceof
|
return
|
transient
|
catch
|
extends
|
int
|
short
|
try
|
char
|
final
|
interface
|
static
|
void
|
class
|
finally
|
long
|
strictfp
|
volatile
|
const
|
float
|
native
|
super
|
while
|
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