Java is a high-level programming language developed by Sun Microsystems. It was originally designed for developing programs for set-top boxes and handheld devices, but later became a popular choice for creating web applications.
The Java syntax is similar to C++, but is strictly an object-oriented programming language. For example, most Java programs contain classes, which are used to define objects, and methods, which are assigned to individual classes. Java is also known for being more strict than C++, meaning variables and functions must be explicitly defined. This means Java source code may produce errors or "exceptions" more easily than other languages, but it also limits other types of errors that may be caused by undefined variables or unassigned types.

Like Java, this is a programming language designed by Sun Microsystems, in conjunction with Netscape, that can be integrated into standard HTML pages. While JavaScript is based on the Java syntax, it is a scripting language, and therefore cannot be used to create stand-alone programs. Instead, it is used mainly to create dynamic, interactive Web pages. For example, Web developers can use JavaScript to validate form input, create image rollovers, and to open those annoying pop-up windows. Like so many other things, we have to take the good with the bad.
The term actually stands for "Joint Photographic Experts Group," because that is the name of the committee that developed the format. But you don't have to remember that because even computer nerds will think you're weird if you mention what JPEG stands for. Instead, remember that a JPEG is a compressed image file format. JPEG images are not limited to a certain amount of color, like GIF images are. Therefore, the JPEG format is best for compressing photographic images. So if you see a large, colorful image on the Web, it is most likely a JPEG file.
While JPEG images can contain colorful, high-resolution image data, it is a lossy format, which means some quality is lost when the image is compressed. If the image is compressed too much, the graphics become noticeably "blocky" and some of the detail is lost. Like GIFs, JPEGs arecrossplatform, meaning the same file will look the same on both a Mac and PC.


Stands for "Java Runtime Environment" and may also be written "Java RTE." Java is a programming language, similar to C. However, since it is a newer language, it is not natively supported by all operating systems. Therefore, a Java Runtime Environment may need to be installed on your computer for Java applets and Java applications to run.
The JRE, or Java RTE, is developed by Sun Microsystems (the creator of Java) and includes the Java Virtual Machine (JVM), code libraries, and components, which are necessary to run programs written in Java. The JRE is available for multiple computer platforms, including Mac, Windows, and Unix.
If the JRE is not installed on a computer, Java programs may not be recognized by the operating system and will not run. The JRE software provides a runtime environment in which Java programs can be executed, just like software programs that have been fully compiled for the computer's processor. JRE software is available as both a standalone environment and a Web browser plug-in, which allows Java applets to be run within a Web browser.
A joystick is an input device commonly used to control video games. Joysticks consist of a base and a stick that can be moved in any direction. The stick can be moved slowly or quickly and in different amounts. Some joysticks have sticks that can also be rotated to the left or right. Because of the flexible movements a joystick allows, it can provide much greater control than the keys on a keyboard.
Joysticks typically include several buttons as well. Most joysticks have at least one button on the top of the stick and another button in the front of the stick for the trigger. Many joysticks also include other buttons on the base that can be pressed using the hand that is not guiding the stick. Joysticks typically connect to your computer using a basicUSB or serial port connection and often come with software that allows you to assign the function of each button.
Since joysticks emulate the controls of planes and other aircraft, they are best suited for flight simulators and flying action games. However, some gamers like to use joysticks for other types of video games, such as first-person shooters and fighting games. Others prefer using the basic keyboard and mouse, with which they are already accustomed to.Jumper:This is a small metal connector that acts as an on/off switch and is used to alter hardware configurations. A jumper is typically made of two wires and a small piece of metal. When the wires are connected by the metal piece, the jumper is turned on, completing the circuit. When the wires are disconnected, the jumper is turned off. Mulitple jumpers, referred to collectively as a jumper block, are often used to tell the computer how a certain device, such as a hard drive or a modem, is configured. They can be found on motherboards, sound cards, graphics cards, I/O cards, CD-ROM interface boards, modems, and hard drive controller boards, and others.
Manually setting jumpers can be a confusing process, so most hardware usually comes with the necessary jumpers preset. If they are not preset, there should be documentation with a clear diagram of the jumper settings included with the hardware. Fortunately, a lot of plug-and-play equipment available today does not require any jumpers. These devices can be configured through a user-friendly interface on your computer.