Java Reference
In-Depth Information
Car yourCar = new Car("Mazda", "RX-8", 2);
yourCar.printDetails();
}
}
amethod'sname begins with alowercase letter,andthe first letter ofeach subsequent
word in a multiword method name is capitalized.
Methodsarelikeconstructorsinthattheyhaveparameterlists.Youpassargumentsto
theseparameterswhenyoucallthemethod.Because
printDetails()
doesnottake
arguments, its parameter list is empty.
Note
Amethod'snameandthenumber,types,andorderofitsparametersareknown
as its
signature
.
When a method is invoked, the code within its body is executed. In the case of
printDetails()
, this method's body executes a sequence of
Sys-
tem.out.println()
method calls to output the values of its
make
,
model
, and
numDoors
instance fields.
Unlike constructors, methods are declared to have return types. A return type iden-
tifies the kind of values returned by the method (e.g.,
int count()
returns 32-bit
integers). If a method does not return a value (and
printDetails()
does not), its
return type is replaced with keyword
void
, as in
void printDetails()
.
Note
Constructors don't have return types because they cannot return values. If a
constructor could return an arbitrary value, how would that value be returned? After
all,the
new
operatorreturnsareferencetoanobject,andhowcould
new
alsoreturna
constructor value?
Amethodisinvokedbyusingthememberaccessoperator;theleftoperandspecifies
the object's reference and the right operand specifies the method to be called. For ex-
ample, the
myCar.printDetails()
and
yourCar.printDetails()
expres-
sions invoke the
printDetails()
instance method on the
myCar
and
yourCar
objects.
You should observe the following output, whose different instance field values prove
that
printDetails()
associates with an object:
