applet is a mini-program that will run only
under a Web browser. The applet is downloaded
automatically as part of a Web page. When the
applet is activated it executes a program. This
is part of its beauty Ė it provides you with
a way to automatically distribute the client
software from the server at the time the user
needs the client software, and no sooner. They
get the latest version of the client software
without fail and without difficult re-installation.
Because of the way
Java is designed, the programmer needs to create
only a single program, and that program automatically
works with all computers that have browsers
with built-in Java interpreters.
are Java programs that execute within the context
of a Web page. They interact with the user while
his Web page is active and stop their execution
when his Web page is no longer active. Applets
are valuable because they are simple to use.
A user only needs to open an applet's Web page
to download and execute an applet.
Java applets, are run from inside a browser.
A reference to an applet is embedded in a Web
page using a special HTML tag. When a reader,
using a Java-enabled browser, loads a Web page
with an applet in it, the browser downloads
that applet from a Web server and executes it
on the local system Because Java applets run
inside a Java browser, they have access to the
structure the browser provides: an existing
window, an event-handling and graphics context,
and the surrounding user interface.
advantage a Java applet has over a scripted
program is that itís in compiled form, so the
source code isnít available to the client.
security is a major concern among Web users
and applet developers. From a user's perspective,
an exploitable applet security flaw could result
in sensitive data being modified or disclosed,
or their computer being rendered inoperable.
From a developer's perspective, strong applet
security is necessary to make Web users comfortable
with using applets. However, too high a level
of security limits their applets' capabilities.