and we are looking now
at how Java works
and what you would do once you have
many classes
so for each Java class that you
write
for each program that you write
you are going to have a .java file
and a corresponding .class file
if you were
writing Java professionally
for a living
you would have dozens
of .class files
and maybe even more than that
now if you are working
on a number
of different projects
you would like to
logically and physically
group all those.class files
so the way that you organize
most people organize the files
on their computers using
separate directories
so what Sun Microsystems did
is they defined the concept
of a package
and a package
is essentially a directory
that holds a number
of classes in it
it is physically a directory
on your hard drive
logically it is just a hierarchy
that you set up
of all your classes
for example
if you are working on three different project
A,B, and C
you would have three different packages
because all your classes on project A
are separate logically from all
of your classes
on project B
ok
there's a way there for you
to share your classes
if you're writing utilities
that you would like to use
on all three of your projects
A,B, and C