Java Reference
In-Depth Information
place the following archive argument in the applet tag:
archive = "Apple.jar"
Now, only one file has to be retrieved instead of many.
We have neglected to talk about passing parameters to the applet through the
applet tag. See any html manual for a complete discussion of applet tags.
Concluding remarks
There are many more html tags, for example for linking to images and set-
ting tables of data, but they should not be hard to learn.
A word of caution in using html the way we have shown. The trend is to
eschew tags like <font> , <b> , <i> , and <u> and to use styles instead —this is not
the place to explain styles. For now, there is nothing wrong with trying to write
a few web pages using the commands we have described simply to get a feel for
how html works.
Several software applications can help you write html pages without actual-
ly requiring you to look at the source html. Netscape Communicator is perhaps
the simplest and is useful when one or two web pages have to be written. When
a large web site is to be designed and implemented, one often use Macromedia's
DreamWeaver or Microsoft's FrontPage .
Security with applets
Security is an important topic, given the current rash of attempts to break
into and destroy people's web sites and computers. Lesson page 16-2 of
ProgramLive contains a footnote that explains why applets are safe.
Key concepts
• Java application . An application is a set of Java classes in which some class
has a static procedure main , with a single parameter of type String[] .
• Jar file . A java application can be packaged in a jar file as a stand-alone appli-
cation. It can then be executed with the jar command or by double clicking on it.
• Java applet . An applet is a Java class that is a subclass of class Applet . The
subclass can override inherited procedures paint , init , start , stop , and
destroy in order to have the applet do something. Use class JApplet (which is
a subclass of Applet ) in the Swing package, instead of Applet .
• Html and the applet tag . Html (HyperText Markup Language) is the language
in which web pages are written. An applet can be included on a page using the
applet tag. For efficiency, the classes that make up an applet can be placed in a
jar file.
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