Java Network Support

Early in Java's history, Java was closely tied to the Internet in people's minds. The reason was a kind of program called an applet. An applet was a small program that was transmitted over the Internet and run on a web page. This article follows that idea step by step, then shows how Java's role on the Internet changed, and why Java's network support and platform independence still matter today.

The applet model can be read as a chain of three events. First, transmission makes the program available over the Internet. Second, the web page runs the program. Third, the page can then support complex tasks and user interaction. Notice that the program itself is not stored in the page in advance as the main content. It arrives over the network and then takes part in what the page does.

Applets were one of Java's major attractions when Java was introduced. They showed that a web page could include a program capable of complex tasks and complex interactions with the user. This was a significant idea at the time: a page could go beyond static information and become interactive through a program that was delivered with it.

However, applets experienced various problems. As a result, they are no longer used, and other options now exist for running programs on web pages. The source does not list the specific problems, so this article does not name them. The important lesson is historical: the applet was a major step in connecting Java with web pages, and it was later replaced by other approaches.

Java's Internet role did not end when applets declined. Java can still be used to create complex stand-alone applications that do not depend on a web browser, and many of these applications are network-related. In addition, many of the largest and most complex web sites use web server software written in Java. The shift is from a small program running on a page to Java software supporting larger Internet systems.

Java includes excellent support for network protocols. This matters because Internet applications and other network-related programs need to communicate using network rules and conventions. Java's network protocol support is one of the reasons it can be used for Internet applications.

The source also connects Java's platform independence with portability. A network program can be written so that it works on many different types of computer. Network support and platform independence therefore reinforce each other: the network support lets the program talk over the Internet, and platform independence lets that same kind of program be used across different machines.