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J
Java</dt>
Java is a programming language that is commonly used in the development of client-server web applications.
Javascript
A programming language used in creating enhanced Web pages – for example with animated graphics or drop down menus. It can be incorporated into html or other web page languages to create a desired effect.
JDBC
Stands for "Java Database Connectivity." JDBC is an API that allows Java applications to connect to and query a wide range of databases. Examples include Java DB, Oracle, MySQL, PostgreSQL, DB2, Sybase ASE, and Microsoft SQL Server.
JDBC makes it possible for a software developer to run SQL queries within a Java application. The database connection and any required query translations are handled by the JDBC driver. For example, the same Java method can be used to query a MySQL database and a Microsoft SQL Server database. The goal is to provide developers with "write once, run anywhere" functionality, making it easy to work with different types of databases.
In order for an application to use JDBC, the appropriate driver must be installed. Examples include the JDBC Thin driver and the JDBC OCI (Oracle Call Interface) driver. The driver files are available as Java archives (.JAR files), which can be referenced by a Java application. Each Java archive contains .CLASS files that allow Java apps to communicate with different types of databases. Individual classes can be removed to reduce the disk space required by the corresponding Java app.
JFS
Stands for "Journaled File System." JFS is a 64-bit file system created by IBM. The initial version of JFS (also called JFS1) was developed for IBM's AIX operating system and was released in 1990. In 2001, IBM released JFS2 (the Enhanced Journaled File System), as well as a version of JFS that is compatible with the Linux operating system.
The "journaled" aspect of JFS means that the file system keeps tracks of changes to files and folders in a log file (or journal). This log can be used to backtrack certain changes in case of an unexpected power failure or system crash, which may prevent data corruption. For example, if a file is in the process of being moved or deleted when a computer crashes, the journal can be used to restore the file to its last stable state. Without the journal, the file may be truncated, which would make it unreadable and could produce other file system errors.
The Enhanced Journaled File System (JFS2) is similar to JFS, but supports much larger volumes and file sizes. For example, a hard disk formatted using JFS can be a maximum of one terabyte (TB) in size, while a JFS2-formatted disk can be up to 32 TB. JFS's maximum file size is slightly less than 64 gigabytes (GB), while JFS2 supports file sizes up to 16 TB. This large file capacity is especially important for storing large databases, which are often contained in a single file.
NOTE: JFS2 is supported by AIX 5.1 and later. It is also supported on Linux systems that have the "jfsutils" package installed.
Jitter
Jitter, in networking, refers to small intermittent delays during data transfers. It can be caused by a number of factors including network congestion, collisions, and signal interference.
Technically, jitter is the variation in latency — the delay between when a signal is transmitted and when it is received. All networks experience some amount of latency, especially wide area networks that span across the Internet. This delay, typically measured in milliseconds, can be problematic for real-time applications, such as online gaming, streaming, and digital voice communication. Jitter makes this worse by producing additional delays.
Network jitter causes packets to be sent at irregular intervals. For example, there may be a delay after some packets are sent and then several packets may be sent all at once. This may cause packet loss if the receiving system is unable to process all the incoming packets. If this happens during a file download, the lost packets will be resent, slowing down the file transfer. In the case of a real-time service, like audio streaming, the data may simply be lost, causing the audio signal to drop out or decrease in quality.
The standard way to compensate for network jitter is to use a buffer that stores data before it is used, such as a few seconds of an audio or video clip. This will smooth out the playback of the media since it gives the receiving computer a few seconds to receive any packets lost due to jitter. While buffers are an effective solution, they must be extremely small when used in real-time applications such as online gaming and video conferencing. If the buffer is too large (greater than 10 ms), it will cause a noticeable delay.
Joystick
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 basic USB 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.
JPEG
JPEG stands for Joint Photographic Experts Group, which was the committee that created the file format known as JPEG. The format is commonlyl used for photos displayed on the world wide web.
jQuery
jQuery is a JavaScript library that allows web developers to add extra functionality to their websites. It is open source and provided for free under the MIT license. In recent years, jQuery has become the most popular JavaScript library used in web development.
To implement jQuery, a web developer simply needs to reference the jQuery JavaScript file within the HTML of a webpage. Some websites host their own local copy of jQuery, while others simply reference the library hosted by Google or the jQuery server. For example, a webpage may load the jQuery library using the line within the head section of the HTML.
Once the jQuery library is loaded, a webpage can call any jQuery function supported by the library. Common examples include modifying text, processing form data, moving elements on a page, and performing animations. jQuery can also work with Ajax code and scripting languages, such as PHP and ASP to access data from a database. Since jQuery runs on the client side (rather than the web server), it can update information on a webpage in realtime, without reloading the page. A common example is "autocomplete," in which a search form automatically displays common searches as you type your query. In fact, this is how TechTerms.com provides search suggestions when you type in the search box.
Besides its free license, the other main reason jQuery has gained such popularity is its cross-browser compatibility. Since each browser renders HTML, CSS, and JavaScript differently, it can be difficult for a web developer to make a website appear the same across all browsers. Instead of having to write custom functions for each browser, a web developer can use a single jQuery function that will work in Chrome, Safari, Firefox, and Internet Explorer. This multi-browser support has led many developers to switch from standard JavaScript to jQuery, since it greatly simplifies the coding process.
You can read more about jQuery and download the latest library at the official jQuery website.
JRE
Besides its free license, the other main reason jQuery has gained such popularity is its cross-browser compatibility. Since each browser renders HTML, CSS, and JavaScript differently, it can be difficult for a web developer to make a website appear the same across all browsers. Instead of having to write custom functions for each browser, a web developer can use a single jQuery function that will work in Chrome, Safari, Firefox, and Internet Explorer. This multi-browser support has led many developers to switch from standard JavaScript to jQuery, since it greatly simplifies the coding process.
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.
Jumpdrive
- referred to as a USB flash drive, data stick, pen drive, keychain drive or thumb drive.
- a portable drive, often the size of your thumb, that connects to the USB port of a computer to allow an
easy way to transfer and store information
- external drives that hold 256MB, 512MB, 1GB, 5GB,and 16GB of information
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