HomeJava & J2EE Page 4 - Primitive Data Types and Basic Language Rules for Java
A Few More Rules - Java
Last time we discussed some basic concepts related to object-oriented programming. Two major ideas we defined were objects and variables. In this article, we will continue our discussion of variables by explaining how they hold and interact with data.
Java likes to separate the men from the boys, the hair from your head, and the code that you write. To do this, we use separators (didn't see that coming did you?).
Separators
Below is a list of separators and their functions.
How it Looks
Name
Function
.
Period
Separates package names from subpackages and classes. Can also be used to separate a variable or method from a reference variable.
;
Semicolon
Ends statements.
,
Comma
Separates identifiers when declaring variables.
{}
Braces
No not for your teeth. Contains the values of initialized arrays. Also for declining a block of code, classes, methods, local scopes.
[]
Brackets
For declaration of array types or dereferencing array values.
()
Parentheses
Holds lists of parameters in method definition, defining precedence in expressions, holding expressions in control statements, and encasing cast types
Keywords
As part of its diverse vocabulary, Java has 49 reserved keywords. These keywords cannot be used to name a variable, class, or method, and will not magically open doors (rely on good ole' "open sesame" for that one). You want to see what they look like in a table? Well here they are:
abstract
assert
boolean
break
byte
case
catch
char
class
const
continue
default
do
double
else
extends
final
finally
float
for
goto
if
implements
import
instanceof
int
interface
long
native
new
package
private
protected
public
return
short
static
strictfp
super
switch
synchronized
this
throw
throws
transient
try
void
volatile
while
Final Notes
That concludes this episode of Beginning Java Programs. In the next article we will discuss Operators and putting those lazy variables to work.
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