Java Reference
In-Depth Information
You should call the file that contains this program
VehicleDemo.java
because the
main(
)
method is in the class called
VehicleDemo
, not the class called
Vehicle
. When you com-
pile this program, you will find that two
.class
files have been created, one for
Vehicle
and one for
VehicleDemo
. The Java compiler automatically puts each class into its own
.class
file. It is not necessary for both the
Vehicle
and the
VehicleDemo
class to be in
the same source file. You could put each class in its own file, called
Vehicle.java
and
Ve-
hicleDemo.java
, respectively.
To run this program, you must execute
VehicleDemo.class
. The following output is dis-
played:
Before moving on, let's review a fundamental principle: each object has its own copies
of the instance variables defined by its class. Thus, the contents of the variables in one ob-
