J
J# (pronounced "J Sharp")
A programming language very similar to Java but implemented in the Microsoft.Net Framework

jack
A connector into which a plug can be connected.

jaggies
The property of an improperly sized bitmap that shows the image broken into blocky squares.

JAR file (Java Archive)
A file containing a collection of Java class files that can be downloaded more efficiently than would be possible if each file were downloaded seperately.

Jargon File
A glossary of computer terms begun at Stanford University in 1975, extensively enlarged at MIT, and eventually published, in a highly revised form, as The New Hacker's Dictionary, by Eric Raymond.

Java
A programming language developed at Sun Microsystems in the mid-1990s, to enable networked computers to transmit computations to each other, not just data.

Java Bean
A software component written in Java. The goal of JavaBeans is to facilitate software development by letting programmers assemble programs from previously written and tested components.

JavaScript
A language that allows a web page to include commands to be executed by the web browser.

J/C
Online abbreviation for "just chilling."

JCL (Job Control Language)
The command language used in batch jobs to tell a computer what to do.

JDK (Java Devlopment Kit)
A system provided free by Sun Microsystems that can be used to write Java programs.

Jerusalem
One of the earliest MS-DOS file infector viruses known to be in the wild. Originally discovered and probably written in Israel. Originally known as the Israeli virus. It has also been called the PLO, Friday the 13th, and 1813. Still one of the file infecting viral programs and widely used as a template for the development of variant viral strains.

jewel case
A rigid, clear plastic case that protects compact discs (CDs).

JIT compliler (Just In Time Compiler)
A compiler that converts intermediate code into native machine language the first time it is encountered.

Johansen, Jon Lech
A Norwegian cracker famous for designing software that could crack the encryption of DVDs.

Joliet file system
An extension of the ISO 9660 format for recording CD-ROMs, created by Microsoft in order to support long filenames and long directory names.

joo
Another word for "you."

joule
A unit for measuring amounts of energy.

journaling
Storage, or transfer to storage, of transcations, rather than the resultant data.

joystick
A computer input device especially helpful when playing computer games.

JPEG (Joint Photographic Experts Group)
A file format for storing bitmap images, including lossy compression.

jukebox
A device for automatically selecting disks (usually CD-ROMs) from a library and inserting the desired one into the disk drive.

Julian calendar
The calendar intorduced in 46 B.C.E. by Julius Caesar, with a leap year every four years.

JumpDrive
Lexar's trademark for a brand of USB flash drive.

jumper
A removable electrical connector that joins two pins on a circuit board.

jump list
A web page consisting mostly of links to other web pages.

junction
The part of a diode or transistor where two opposite types of semiconductor material meet.

junk email
Unsolicited electronic mail.

junk fax
An unsolicited advertisement transmitted by fax.

jurisdiction
A physical land area or geographical district.

justification
The insertion of extra space between words in lines of type so that the left and right margins are even and smooth.

Just in Time (JIT) Compiler
Translates JAVA bytecode into machine language while the bytecode is being executed.

JVM (Java Virtual Machine)
Software that executes java bytecode.

Jython
An implementation of Python based on Java.