Java Reference
In-Depth Information
class Date1 {
public static void main(String[] args) {
java.util.Date now = new java.util.Date();
System.out.println(now);
}
}
And here is a version that uses
import
to declare the type
Date
:
import java.util.Date;
class Date2 {
public static void main(String[] args) {
Date now = new Date();
System.out.println(now);
}
}
When the compiler comes to the declaration of
now
it determines that
the
Date
type is actually the
java.util.Date
type, because that is the only
Date
type it knows about. Import statements simply provide information
to the compiler; they don't cause files to be "included" into the current
file.
The name collision problem is not completely solved by the package
mechanism. Two projects can still give their packages the same name.
This problem can be solved only by convention. The standard convention
is to use the reversed Internet domain name of the organization to pre-
fix the package name. For example, if the Acme Corporation had the
Internet domain
acme.com
, it would use package names starting with
com.acme
, as in
com.acme.tools
.
Classes are always part of a package. A package is named by providing
a package declaration at the top of the source file:
