Enter Java, and the capability for Web pages of containing Java applets. Applets are small programs that create animations, multimedia presentations, real-time (video) games, multi-user networked games, and real interactivity—in fact, most anything a small program can do, Java applets can. Downloaded over the net and executed inside a Web page by a browser that supports

Java, applets are an enormous step beyond standard Web design. The disadvantage of Java is that to create Java applets right now, you need to write them in the Java language. Java is a programming language, and as such, creating Java applets is more difficult than creating a Web page or a form using HTML. Soon there will be tools and programs that will make creating Java applets easier—they may be available by the time you read this. For now, however, the only way to delve into Java is to learn the language and start playing with the raw Java code. Even when the tools come out, we may want to do more with Java than the tools can provide, and we’re back to learning the language.


A computer is a device capable of performing computations and making logical decisions at speeds millions (even billions) of times faster than human beings can. For example, many of today’s personal computers can perform several billion calculations in one second. A person operating a desk calculator could not perform that many calculations in a lifetime. (Points to ponder: How would you know whether the person added the numbers correctly? How would you know whether the computer added the numbers correctly?) Today’s fastest supercomputers are already performing trillions of instructions per second!

Computers process data under the control of sets of instructions called computer programs.

These programs guide the computer through orderly sets of actions specified by people called computer programmers.

A computer consists of various devices referred to as hardware (e.g., the keyboard, screen, mouse, disks, memory, DVD, CD-ROM and processing units). The programs that run on a computer are referred to as software. Hardware costs have been declining dramatically in recent years, to the point that personal computers have become a commodity.

Most people are familiar with the exciting tasks computers perform. It is software (i.e., the instructions you write to command computers to perform actions and make decisions) that controls computers (often referred to as hardware). Java, developed by Sun Microsystems, is one of today’s most popular software development languages.

Computer use is increasing in almost every field of endeavor. Computing costs have been decreasing dramatically due to rapid developments in both hardware and software technologies.

Computers that might have filled large rooms and cost millions of dollars decades ago can now be inscribed on silicon chips smaller than a fingernail, costing perhaps a few dollars each. Fortunately, silicon is one of the most abundant materials on earth—it is an ingredient in common sand. Silicon chip technology has made computing so economical that about a billion general-purpose computers are in use worldwide, helping people in business, industry and government, and in their personal lives. The number could easily double in the next few years.

Over the years, many programmers learned the programming methodology called structured programming. But there is an exciting newer methodology, object-oriented programming although it is advisable to study both. Object orientation is the key programming methodology used by programmers today, but the internal structure is often built using structured-programming techniques. Also, the logic of manipulating objects is occasionally expressed with structured programming.