Java 2 Platform, Enterprise Edition (J2EE) is a Java platform designed for the mainframe-scale computing typical of large enterprises. Sun Microsystems (together with industry partners such as IBM) designed J2EE to simplify application development in a thin client tier ed environment. J2EE simplifies application development and decreases the need for programming and programmer training by creating standardized, reusable modular components and by enabling the tier to handle many aspects of programming automatically.
J2EE includes many components of the Java 2 Platform, Standard Edition (J2SE):
* The Java Development Kit (JDK) is included as the core language package.
* Write Once Run Anywhere technology is included to ensure portability.
* Support is provided for Common Object Request Broker Architecture (CORBA), a predecessor of Enterprise JavaBeans (EJB), so that Java objects can communicate with CORBA objects both locally and over a network through its interface broker.
* Java Database Connectivity 2.0 (JDBC), the Java equivalent to Open Database Connectivity (ODBC), is included as the standard interface for Java databases.
* A security model is included to protect data both locally and in Web-based applications.
J2EE also includes a number of components added to the J2SE model, such as the following:
* Full support is included for Enterprise JavaBeans. EJB is a server-based technology for the delivery of program components in an enterprise environment. It supports the Extensible Markup Language (XML) and has enhanced deployment and security features.
* The Java servlet API (application programming interface) enhances consistency for developers without requiring a graphical user interface (GUI).
* Java Server Pages (JSP) is the Java equivalent to Microsoft's Active Server Pages (ASP) and is used for dynamic Web-enabled data access and manipulation.
The J2EE architecture consists of four major elements:
* The J2EE Application Programming Model is the standard programming model used to facilitate the development of multi-tier, thin client applications.
* The J2EE Platform includes necessary policies and APIs such as the Java servlets and Java Message Service (JMS).
* The J2EE Compatibility Test Suite ensures that J2EE products are compatible with the platform standards.
* The J2EE Reference Implementation explains J2EE capabilities and provides its operational definition.
J2ME - Java 2 Platform, Micro Edition:
Java 2 Platform, Micro Edition (J2ME) is a technology that allows programmers to use the Java programming language and related tools to develop programs for mobile wireless information devices such as cellular phones and personal digital assistants (PDAs). J2ME consists of programming specifications and a special virtual machine, the K Virtual Machine, that allows a J2ME-encoded program to run in the mobile device.
There are two programming specifications: Connected, Limited Device Configuration (CLDC) and the Mobile Information Device Profile (MIDP). CLDC lays out the application program interface (API) and virtual machine features needed to support mobile devices. MIDP adds to the CLDC the user interface, networking, and messaging details needed to interface with mobile devices. MIDP includes the idea of a midlet, a small Java application similar to an applet but one that conforms with CLDC and MIDP and is intended for mobile devices.
Devices with systems that exploit J2ME are already available and are expected to become even more available in the next few years.
Jabber is an initiative to produce an open source, XML-based instant messaging platform. Similar to the Linux and Apache projects, Jabber developers volunteer their time to work with the code over the Internet. As a result of their efforts, anyone can download the Jabber client and server for free. Creator Jeremie Miller first started Jabber.org in 1998.
Jabber operates differently than other proprietary instant messaging systems and works in a fashion similar to e-mail, using a distributed architecture. It adds a suffix to each address after the "@" sign (for instance user@msn) just like an e-mail addressing system. This enables a Jabber server to read addresses from different messaging systems and know where they can be found.
Even though Jabber is offered for free, many businesses need a contact for packaged software, technical support, and other services. That's the niche that Jabber.com hopes to fill. The company calls its relationship to Jabber.org similar to the one Red Hat has with Linux. Jabber.com has already released an instant messaging server that it vows will be compatible with many existing platforms, including America Online's closely guarded ICQ and AOL Instant Messenger. Miller now works for Jabber.com.
In September 2000, Jabber.com signed a deal with an open-source application service provider (ASP) and a wireless application developer to make a version for mobile devices.
Jabber (in networks):
In networks, a Jabber is any device that is handling electrical signals improperly, usually affecting the rest of the network. In an Ethernet network, devices compete for use of the line, attempting to send a signal and then retrying in the event that someone else tried at the same time. A jabber can look like a device that is always sending, effectively bringing the network to a halt. A jabber is usually the result of a bad network interface card (NIC). Occasionally, it can be caused by outside electrical interference.
Java is a programming language expressly designed for use in the distributed environment of the Internet. It was designed to have the "look and feel" of the C++ language, but it is simpler to use than C++ and enforces an object-oriented programming model. Java can be used to create complete applications that may run on a single computer or be distributed among servers and clients in a network. It can also be used to build a small application module or applet for use as part of a Web page. Applets make it possible for a Web page user to interact with the page.
The major characteristics of Java are:
* The programs you create are portable in a network. (See portability.) Your source program is compiled into what Java calls bytecode, which can be run anywhere in a network on a server or client that has a Java virtual machine . The Java virtual machine interprets the bytecode into code that will run on the real computer hardware. This means that individual computer platform differences such as instruction lengths can be recognized and accommodated locally just as the program is being executed. Platform-specific versions of your program are no longer needed.
* The code is robust , here meaning that, unlike programs written in C++ and perhaps some other languages, the Java objects can contain no references to data external to themselves or other known objects. This ensures that an instruction can not contain the address of data storage in another application or in the operating system itself, either of which would cause the program and perhaps the operating system itself to terminate or "crash." The Java virtual machine makes a number of checks on each object to ensure integrity.
* Java is object-oriented, which means that, among other characteristics, an object can take advantage of being part of a class of objects and inherit code that is common to the class. Objects are thought of as "nouns" that a user might relate to rather than the traditional procedural "verbs." A method can be thought of as one of the object's capabilities or behaviors.
* In addition to being executed at the client rather than the server, a Java applet has other characteristics designed to make it run fast.
* Relative to C++, Java is easier to learn. (However, it is not a language you'll pick up in an evening!)
Java was introduced by Sun Microsystems in 1995 and instantly created a new sense of the interactive possibilities of the Web. Both of the major Web browsers include a Java virtual machine. Almost all major operating system developers (IBM, Microsoft, and others) have added Java compilers as part of their product offerings.
The Java virtual machine includes an optional just-in-time compiler that dynamically compiles bytecode into executable code as an alternative to interpreting one bytecode instruction at a time. In many cases, the dynamic JIT compilation is faster than the virtual machine interpretation.
JavaBeans is an object-oriented programming interface from Sun Microsystems that lets you build re-useable applications or program building blocks called components that can be deployed in a network on any major operating system platform. Like Java applet, JavaBeans components (or "Bean s") can be used to give World Wide Web pages (or other applications) interactive capabilities such as computing interest rates or varying page content based on user or browser characteristics.
From a user's point-of-view, a component can be a button that you interact with or a small calculating program that gets initiated when you press the button. From a developer's point-of-view, the button component and the calculator component are created separately and can then be used together or in different combinations with other components in different applications or situations.
When the components or Beans are in use, the properties of a Bean (for example, the background color of a window) are visible to other Beans and Beans that haven't "met" before can learn each other's properties dynamically and interact accordingly.
Beans are developed with a Beans Development Kit (BDK) from Sun and can be run on any major operating system platform (Windows 95, UNIX, Mac) inside a number of application environments (known as containers), including browsers, word processors, and other applications.
To build a component with JavaBeans, you write language statements using Sun's Java programming language and include JavaBeans statements that describe component properties such as user interface characteristics and events that trigger a bean to communicate with other beans in the same container or elsewhere in the network.
Beans also have persistence, which is a mechanism for storing the state of a component in a safe place. This would allow, for example, a component (bean) to "remember" data that a particular user had already entered in an earlier user session. JavaBeans gives Java applications the compound document capability that the OpenDoc and ActiveX interfaces already provide.
Java Foundation Classes - JFC:
Using the Java programming language, Java Foundation Classes (JFC) are pre-written code in the form of class libraries (coded routines) that give the programmer a comprehensive set of graphical user interface (GUI) routines to use. The Java Foundation Classes are comparable to the Microsoft Foundation Class (MFC) library. JFC is an extension of the original Java Abstract Windowing Toolkit (AWT). Using JFC and Swing, an additional set of program components, a programmer can write programs that are independent of the windowing system within a particular operating system.
Java Message Service - JMS:
Java Message Service (JMS) is an application program interface (API) from Sun Microsystems that supports the formal communication known as messaging between computers in a network. Sun's JMS provides a common interface to standard messaging protocols and also to special messaging services in support of Java programs. Sun advocates the use of the Java Message Service for anyone developing Java applications, which can be run from any major operating system platform.
The messages involved exchange crucial data between computers - rather than between users - and contain information such as event notification and service requests. Messaging is often used to coordinate programs in dissimilar systems or written in different programming languages. Using the JMS interface, a programmer can invoke the messaging services of IBM's MQSeries , Progress Software's SonicMQ, and other popular messaging product vendors. In addition, JMS supports messages that contain serialized Java objects and messages that contain Extensible Markup Language (XML) pages.
Java Naming and Directory Interface - JNDI:
Java Naming and Directory Interface (JNDI) enables Java platform-based applications to access multiple naming and directory services. Part of the Java Enterprise application programming interface (API) set, JNDI makes it possible for developers to create portable applications that are enabled for a number of different naming and directory services, including: file systems; directory services such as Lightweight Directory Access Protocol (LDAP), Novell Directory Services, and Network Information System (NIS); and distributed object systems such as the Common Object Request Broker Architecture (CORBA), Java Remote Method Invocation (RMI), and Enterprise JavaBeans (EJB).
As an illustration of what JNDI does, Todd Sundsted (in a JavaWorld article, JNDI overview, Part 1: An introduction to naming services) uses the analogy of a library's file system. Sundsted says that JNDI organizes and locates components within a distributed computing environment similarly to the way that card catalogs (and increasingly computer applications) organize and represent the locations of books within a library. A distributed application needs a means of locating components in the same way that the library patron needs a means of locating the book: just rummaging around inside a library - or an application - is not an efficient way to find a particular object. JNDI makes it possible for application components to find each other. Because different naming and directory service providers can be seamlessly connected through the API, Java applications using it can be easily integrated into various environments and coexist with legacy application s. The current version, JNDI 1.2, was specified with input from Netscape, Novell, Tarantella, Sun, and BEA. JNDI is considered an industry standard.
Java Online Analytical Processing - JOLAP:
Java Online Analytical Processing (JOLAP) is a Java application-programming interface (API) for the Java 2 Platform, Enterprise Edition (J2EE) environment that supports the creation, storage, access, and management of data in an online analytical processing (OLAP) application. Hyperion, IBM, and Oracle initiated the development of JOLAP intending it to be a counterpart to Java Database Connectivity (JDBC) specifically for OLAP. The Java Community Process 2.0 (JCP) program oversees the JOLAP development process. The final version of JOLAP is expected in early 2003.
Java Server Page - JSP:
Java Server Page (JSP) is a technology for controlling the content or appearance of Web pages through the use of servlet s, small programs that are specified in the Web page and run on the Web server to modify the Web page before it is sent to the user who requested it. Sun Microsystems, the developer of Java, also refers to the JSP technology as the Servlet application program interface (API). JSP is comparable to Microsoft's Active Server Page (ASP ) technology. Whereas a Java Server Page calls a Java program that is executed by the Web server, an Active Server Page contains a script that is interpreted by a script interpreter (such as VBScript or JScript) before the page is sent to the user.
An HTML page that contains a link to a Java servlet is sometimes given the file name suffix of .JSP.
* Automatically change a formatted date on a Web page
* Cause a linked-to page to appear in a popup window
* Cause text or a graphic image to change during a mouse rollover
Java within Hypertext Markup Language - JHTML:
Java within Hypertext Markup Language (JHTML) is a standard for including a Java program as part of a Web page (a page written using the Hypertext Markup Language, or HTML). A Web site developer can write a small program using the Java programming language and insert the program within a Web page. When a user requests the page, the Web site server, observing a request for a file with the .jhtml suffix, passes the code to a special Java program designed to handle JHML. This program, called the PageCompileServlet, calls the Java compiler , which quickly compiles the code. (If the code has previously been compiled by an earlier page request, this step is unnecessary.) The code is then executed, typically modifying the contents of the Web page in some way before it is sent to the requestor.
JBOD (for "just a bunch of disks," or sometimes "just a bunch of drives") is a derogatory term - the official term is "spanning" - used to refer to a computer's hard disks that haven't been configured according to the RAID (for "redundant array of independent disks") system to increase fault tolerance and improve data access performance.
The RAID system stores the same data redundantly on multiple disks that nevertheless appear to the operating system as a single disk. Although, JBOD also makes the disks appear to be a single one, it accomplishes that by combining the drives into one larger logical one. JBOD doesn't deliver any advantages over using separate disks independently and doesn't provide any of the fault tolerance or performance benefits of RAID.
A modern dialect composed of butchered English grammar, pervasive with east coast American Jews, and in political arenas. A dialog that is generally pretentious and void of substance. The verbiage typically structured in such a manner so as to sound intellectual in an effort to mask a hollow and or incomplete educational exposure. A frequent affliction of the MBF Twitter and short attention span video game generation. Personified as a lack of competent and disciplined communication skills. Typical indicators of Jewbonics being sentences void of nouns, and or sentence structures leading to the omission of nouns at the sentence terminus.
Extreme example of Jewbonics regarding daily "business" matters: With the increasability in the seasonality of the functionality in profitability along with backwardation and diversification, leading to negativity, reduced tradability, and capitalization, producing nationalization and ...
see Ebonics, and Chinglish
JHTML - Java within Hypertext Markup Language:
See Java within Hypertext Markup Language.
Jitter is the deviation in or displacement of some aspect of the pulses in a high-frequency digital signal . As the name suggests, jitter can be thought of as shaky pulses. The deviation can be in terms of amplitude, phase timing, or the width of the signal pulse. Another definition is that it is "the period frequency displacement of the signal from its ideal location." Among the causes of jitter are electromagnetic interference (EMI) and crosstalk with other signals. Jitter can cause a display monitor to flicker; affect the ability of the processor in a personal computer to perform as intended; introduce clicks or other undesired effects in audio signals, and loss of transmitted data between network devices. The amount of allowable jitter depends greatly on the application.
JMS - Java Message Service:
See Java Message Service.
JNDI - Java Naming and Directory Interface:
See Java Naming and Directory Interface.
In certain computer operating systems, a job is the unit of work that a computer operator (or a program called a job scheduler) gives to the operating system. For example, a job could be the running of an application program such as a weekly payroll program. A job is usually said to be run in batch (rather than interactive) mode. The operator or job scheduler gives the operating system a "batch" of jobs to do (payroll, cost analysis, employee file updating, and so forth) and these are performed in the background when time-sensitive interactive work is not being done. In IBM mainframe operating systems (MVS, OS/390, and successors) a job is described with job control language (JCL). Jobs are broken down into job steps. An example of a job step might be to make sure that a particular data set or database needed in the job is made accessible.
Typically, the development programmer who writes a program that is intended to be run as a batch job also writes the JCL that describes for the operating system how to run the job (for example, what data sets or databases it uses). The use of a job scheduler usually provides greater flexibility and the ability to monitor and report batch job operations. A similar term is task, a concept usually applied to interactive work. A multitasking operating system serving one or more interactive users can at the same time perform batch jobs in the background.
John von Neumann:
John von Neumann was the scientist who conceived a fundamental idea that serves all modern computers - that a computer's program and the data that it processes do not have to be fed into the computer while it is working, but can be kept in the computer's memory - a notion generally referred to as the stored-program computer . In his short life, von Neumann became one of the most acclaimed and lauded scientists of the 20th century. He left an indelible mark on the fields of mathematics, quantum theory, game theory, nuclear physics, and computer science. Born in Budapest, von Neumann was a child prodigy who went on to study chemistry in Berlin and Zurich, where he earned a Diploma in Chemical Engineering in 1926. His doctorate in mathematics (on set theory) from the University of Budapest followed in the same year. After lecturing at Berlin and Hamburg, von Neumann emigrated to the US in 1930 where he worked at Princeton and was one of the founding members of the Institute for Advanced Studies.
At Princeton, von Neumann lectured in the nascent field of quantum theory and through his work on rings of operators (later renamed Neumann algebras) he helped develop the mathematical foundations of that theory which were unveiled in the paper "Mathematische Grundlagen der Quantenmechanik" (1932). His seminal publication on game theory, "Theory of Games and Economic Behaviour" was published in 1934 with co-author Oskar Morgenstern.
Spurred by an interest in hydrodynamics and the difficulty of solving the non-linear partial differential equations involved, von Neumann turned to the emerging field of computing. His first introduction to computers was Howard Aiken's Harvard Mark I. As a consultant to Eckert and Mauchly on the ENIAC, he devised a concept for computer architecture that remains with us to this day. Known subsequently as the "von Neumann architecture", the stored-program computer (where both the instructions and the data they operate upon reside together in memory) with its central controller, I/O, and memory was outlined in a "Draft Report" and paved the way for the modern era of computing. von Neumann was a pioneer in the field of cellular automata (an n-dimensional array of cells where the contents of a cell depend of the contents of neighbouring cells) and also popularized the binary digit as the unit of computer memory.
von Neumann was constantly busy with both his extensive consulting career and his varied research interests. Among his employers was the U.S. military, for whom he worked on the development of the hydrogen bomb. He received the Enrico Fermi award in 1956, the latest in a long line of honors (including 7 honorary doctorates and 2 Presidential Awards). John von Neumann died on February 8, 1957 in Washington D.C.
JOLAP - Java Online Analytical Processing:
See Java Online Analytical Processing.
Joliet is an extension to ISO 9660, the specification for the file system (including file names) for the content on a compact disc (CD); it allows file names up to 64 characters in length (including spaces) and the use of Unicode characters in file names (sometimes needed for internationalization). Written by Microsoft, Joliet is fully supported in Windows 95 and later Windows operating systems (except Windows NT prior to its version 4). In operating systems (such as Windows 3.1) that support only eight-character file names, a longer file name on the CD is truncated into an eight-character name using a tilde (~) followed by a unique number as the last characters in the name.
Code enhancements can be applied to Macintosh and Linux systems that enable Joliet-conforming file names on a CD to be visible to the operating system user.