the language as a whole. Java was the perfect response to the demands of the then newly
emerging, highly distributed computing universe. Java was to Internet programming what
C was to system programming: a revolutionary force that changed the world.
The C# Connection
The reach and power of Java continues to be felt in the world of computer language
development. Many of its innovative features, constructs, and concepts have become part
of the baseline for any new language. The success of Java is simply too important to ignore.
Perhaps the most important example of Java's influence is C#. Created by Microsoft to
support the .NET Framework, C# is closely related to Java. For example, both share the
same general syntax, support distributed programming, and utilize the same object model.
There are, of course, differences between Java and C#, but the overall "look and feel" of
these languages is very similar. This "cross-pollination" from Java to C# is the strongest
testimonial to date that Java redefined the way we think about and use a computer language.
How Java Changed the Internet
The Internet helped catapult Java to the forefront of programming, and Java, in turn, had a
profound effect on the Internet. In addition to simplifying web programming in general,
Java innovated a new type of networked program called the applet that changed the way
the online world thought about content. Java also addressed some of the thorniest issues
associated with the Internet: portability and security. Let's look more closely at each of these.
Java Applets
An applet is a special kind of Java program that is designed to be transmitted over the
Internet and automatically executed by a Java-compatible web browser. Furthermore, an
applet is downloaded on demand, without further interaction with the user. If the user
clicks a link that contains an applet, the applet will be automatically downloaded and run in
the browser. Applets are intended to be small programs. They are typically used to display
data provided by the server, handle user input, or provide simple functions, such as a loan
calculator, that execute locally, rather than on the server. In essence, the applet allows some
functionality to be moved from the server to the client.
The creation of the applet changed Internet programming because it expanded the
universe of objects that can move about freely in cyberspace. In general, there are two very
broad categories of objects that are transmitted between the server and the client: passive
information and dynamic, active programs. For example, when you read your e-mail, you are
viewing passive data. Even when you download a program, the program's code is still only
passive data until you execute it. By contrast, the applet is a dynamic, self-executing program.
Such a program is an active agent on the client computer, yet it is initiated by the server.
As desirable as dynamic, networked programs are, they also present serious problems
in the areas of security and portability. Obviously, a program that downloads and executes
automatically on the client computer must be prevented from doing harm. It must also be
able to run in a variety of different environments and under different operating systems. As
you will see, Java solved these problems in an effective and elegant way. Let's look a bit
more closely at each.
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