import java.awt.event.*;
So all classes in the java.awt.event package can be found (in rt.jar)
and their short names can be used in the source.
import java.awt.event;
is not possible, but maybe you mean something like
import java.awt.event.MouseEvent;
so MouseEvent's full name is known and it can be found in rt.jar .
The above applies to interfaces as well, not just to classes.
--
http://javalessons.com Paul Hamaker, SEMM
Teaching ICT since 1987