what is www?

A technical definition of the World Wide Web is: all the resources and users on the Internet that are using the Hypertext Transfer Protocol (HTTP).

A broader definition comes from the organization that Web inventor Tim Berners-Lee helped found, the World Wide Web Consortium (w3c):

"The World Wide Web is the universe of network-accessible information, an embodiment of human knowledge."

what is intranet?

Intranet is the generic term for a 

collection of private computer networks 

within an organization. An intranet uses 

network technologies as a tool to 

facilitate communication between people 

or workgroups to improve the data 

sharing capability and overall knowledge 

base of an organization's employees.

what is internet?

The Internet, sometimes called simply "the Net," is a worldwide system of computer networks - a network of networks in which users at any one computer can, if they have permission, get information from any other computer (and sometimes talk directly to users at other computers). It was conceived by the Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and was first known as the ARPANET. The original aim was to create a network that would allow users of a research computer at one university to be able to "talk to" research computers at other universities. A side benefit of ARPANet's design was that, because messages could be routed or rerouted in more than one direction, the network could continue to function even if parts of it were destroyed in the event of a military attack or other disaster.

Use Any Phone on Any Wireless Network

The reason most cell phones are so cheap is that wireless carriers subsidize them so you'll sign a long-term contract. Open access could change the economics of the mobile phone (and mobile data) business dramatically as the walls preventing certain devices from working on certain networks come down. We could also see a rapid proliferation of cell phone models, with smaller companies becoming better able to make headway into formerly closed phone markets.

Two years is an eternity in the cellular world. The original iPhone was announced, introduced, and discontinued in less than that time, yet carriers routinely ask you to sign up for two-year contracts if you want access to their discounted phones. (It could be worse--in other countries, three years is normal.) Verizon launched the first volley late last year when it promised that "any device, any application" would soon be allowed on famously closed network . Meanwhile, AT&T and T-Mobile like to note that their GSM networks have long been "open."

Open access is partially here: You can use almost any unlocked GSM handset on AT&T or T-Mobile today, and Verizon Wireless began certifying third-party devices for its network in July (though to date the company has approved only two products). But the future isn't quite so rosy, as Verizon is dragging its feet a bit on the legal requirement that it keep its newly acquired 700-MHz network open to other devices, a mandate that the FCC agreed to after substantial lobbying by Google. Some experts have argued that the FCC provisions aren't wholly enforceable. However, we won't really know how "open" is defined until the new network begins rolling out, a debut slated for 2010.

Google's Desktop OS

In case you haven't noticed, Google now has its well-funded mitts on just about every aspect of computing. From web browsers to cell phones, soon you'll be able to spend all day in the Googleverse and never have to leave. Will Google make the jump to building its own PC operating system next?

 It's everything, or so it seems. Google Checkout provides an alternative to PayPal. Street View is well on its way to taking a picture of every house on every street in the United States. And the fun is just starting: Google's early-beta Chrome browser earned a 1 percent market share in the first 24 hours of its existence. Android, Google's cell phone operating system, is hitting handsets as you read this, becoming the first credible challenger to the iPhone among sophisticated customers.

Though Google seems to have covered everything, many observers believe that logically it will next attempt to attack one very big part of the software market: the operating system.

The Chrome browser is the first toe Google has dipped into these waters. While a browser is how users interact with most of Google's products, making the underlying operating system somewhat irrelevant, Chrome nevertheless needs an OS to operate.

To make Microsoft irrelevant, though, Google would have to work its way through a minefield of device drivers, and even then the result wouldn't be a good solution for people who have specialized application needs, particularly most business users. But a simple Google OS--perhaps one that's basically a customized Linux distribution--combined with cheap hardware could be something that changes the PC landscape in ways that smaller players who have toyed with open-source OSs so far haven't been quite able to do.

Check back in 2011, and take a look at the not-affiliated-with-Google gOS

Windows 7---- It's Inevitable

Whether you love Vista or hate it, the current Windows will soon go to that great digital graveyard in the sky. After the tepid reception Vista received, Microsoft is putting a rush on Vista's follow-up, known currently as windows 7.

 At this point Windows 7 seems to be the os with microsoft wanted to relese as vista, but lacked the time or resources to complete. Besides continuing refinements to the security system of the OS and to its look and feel, Windows 7 may finally bring to fruition the long-rumored database-like WinFS file system. Performance and compatibility improvements over Vista are also expected.

But the main thrust of Windows 7 is likely to be enhanced online integration and more cloud computing future--look for Microsoft to tie its growing Windows Live services into the OS more strongly than ever. Before his retirement as Microsoft's chairman, Bill Gates suggested that a so-called pervasive desktop would be a focus of Windows 7, giving users a way to take all their data, desktop settings, bookmarks, and the like from one computer to another--presumably as long as all those computers were running Windows 7.

 Microsoft has set a target date of January 2010 for the release of Windows 7, and the official date hasn't slipped yet. However, rumor has the first official beta coming out before the end of this year.

Wireless Power Transmission

Wireless power transmission has been a dream since the days when Nikola Tesla imagined a world studded with enormous Tesla coils. But aside from advances in recharging electric toothbrushes, wireless power has so far failed to make significant inroads into consumer-level gear.
This summer, Intel researchers demonstrated a method--based on MIT research--for throwing electricity a distance of a few feet, without wires and without any dangers to bystanders (well, none that they know about yet). Intel calls the technology and it works by sending a specific, 10-MHz signal through a coil of wire; a similar, nearby coil of wire resonates in tune with the frequency, causing electrons to flow through that coil too. Though the design is primitive, it can light up a 60-watt bulb with 70 percent efficiency.

 Numerous obstacles remain, the first of which is that the Intel project uses alternating current. To charge gadgets, we'd have to see a direct-current version, and the size of the apparatus would have to be considerably smaller. Numerous regulatory hurdles would likely have to be cleared in commercializing such a system, and it would have to be thoroughly vetted for safety concerns.
Assuming those all go reasonably well, such receiving circuitry could be integrated into the back of your laptop screen in roughly the next six to eight years. It would then be a simple matter for your local airport or even Starbucks to embed the companion power transmitters right into the walls so you can get a quick charge without ever opening up your laptop bag.

DNS(Domain Name System )

• Short for Domain Name System (or Service or Server), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4.
• The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a      particular domain name, it asks another one, and so on, until the correct IP address is returned.

• Short for digital nervous system, a term coined by Bill Gates to describe a network of personal computers that make it easier to obtain and understand information.

IP address

An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 1.160.10.110 could be an IP address.
Within an isolated network, you can assign IP addresses at random as long as each one is unique. However, connecting a private network to theInternet requires using registered IP addresses (called Internet addresses) to avoid duplicates.

The four numbers in an IP address are used in different ways to identify a particular network and a host on that network. Four regional Internetregistries -- ARIN, RIPE NCC, LACNIC and APNIC -- assign Internet addresses from the following three classes.

·  Class A - supports 16 million hosts on each of 126 networks

·  Class B - supports 65,000 hosts on each of 16,000 networks

·  Class C - supports 254 hosts on each of 2 million networks

The number of unassigned Internet addresses is running out, so a new classless scheme called CIDR is gradually replacing the system based on classes A, B, and C and is tied to adoption of IPv6.

UDP(Usenet Death Penalty)

Abbreviated UDP, a Usenet penalty enforced by system administrators of an ISP or NSP against other service providers. Usenet is by nature cooperative, and the UDP is one way that administrators can handle uncooperative members. UDPs are typically issued to ISP/NSPs that have users that are spamming and that have not stopped the users from doing so even after repeated requests for the administrators to deal with the spam. When a UDP is issued, any messages posted to Usenet from that site will be cancelled. UDPs are also issued to individual spammers

UDP(User Datagram Protocol)

Abbreviated UDP, a connectionless protocol that, like TCP, runs on top of IP networks. Unlike TCP/IP, UDP/IP provides very few error recovery services, offering instead a direct way to send and receive datagrams over an IP network. It's used primarily for broadcasting messages over a network.

TCP

Abbreviation of Transmission Control Protocol, and pronounced as separate letters. TCP is one of the main protocols in TCP/IPnetworks. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent.

What is thread.Explain the concept of Multithreading Programing with an Example?

Definition: A thread is a single sequential flow of control within a program.
Introduction
So far you have learned about a single thread. Lets us know about the concept of multithreading and learn the implementation of it. But before that, lets be aware from the multitasking.
Multitasking :


Multitasking allow to execute more than one tasks at the same time, a task being a program. In multitasking only one CPU is involved but it can switches from one program to another program so quickly that's why it gives the appearance of executing all of the programs at the same time. Multitasking allow processes (i.e. programs) to run concurrently on the program. For Example running the spreadsheet program and you are working with word processor also.
Multitasking is running heavyweight processes by a single OS.
Multithreading :
Multithreading is a technique that allows a program or a process to execute many tasks concurrently (at the same time and parallel). It allows a process to run its tasks in parallel mode on a single processor system
In the multithreading concept, several multiple lightweight processes are run in a single process/task or program by a single processor. For Example, When you use a word processoryou perform a many different tasks such as printing, spell checking and so on. Multithreaded software treats each process as a separate program.
In Java, the Java Virtual Machine (JVM) allows an application to have multiple threads of execution running concurrently. It allows a program to be more responsible to the user. When a program contains multiple threads then the CPU can switch between the two threads to execute them at the same time.
For example, look at the diagram shown as:


In this diagram, two threads are being executed having more than one task. The task of each thread is switched to the task of another thread.
Advantages of multithreading over multitasking :
• Reduces the computation time.
• Improves performance of an application.
• Threads share the same address space so it saves the memory.
• Context switching between threads is usually less expensive than between processes.
• Cost of communication between threads is relatively low.
Different states implementing Multiple-Threads are:
As we have seen different states that may be occur with the single thread. A running thread can enter to any non-runnable state, depending on the circumstances. A thread cannot enters directly to the running state from non-runnable state, firstly it goes to runnable state. Now lets understand the some non-runnable states which may be occur handling the multithreads.
• Sleeping – On this state, the thread is still alive but it is not runnable, it might be return to runnable state later,                           If a particular event occurs. On this state a thread sleeps for a specified amount of time. You can use the  method sleep( ) to stop the running state of a thread.


static void sleep(long millisecond) throws InterruptedException
• Waiting for Notification – A thread waits for notification from another thread. The thread sends back to runnable state after sending notification from another thread.


final void wait(long timeout) throws InterruptedException
final void wait(long timeout, int nanos) throws InterruptedException
final void wait() throws InterruptedException


• Blocked on I/O – The thread waits for completion of blocking operation. A thread can enter on this state because of waiting I/O resource. In that case the thread sends back to runnable state after availability of resources.


• Blocked for joint completion – The thread can come on this state because of waiting the completion of another thread.


• Blocked for lock acquisition – The thread can come on this state because of waiting to acquire the lock of an object.

What is checked exeption and unchecked exeption . Explain some of these exeption with an Example?

In Java there are basically two types of exceptions: Checked exceptions and unchecked exceptions. C# only has unchecked exceptions. The differences between checked and unchecked exceptions are:
1. Checked exceptions must be explicitly caught or propagated as described in Basic try-catch-finally Exception Handling. Unchecked exceptions do not have this requirement. They don't have to be caught or declared thrown.
2. Checked exceptions in Java extend the java.lang.Exception class. Unchecked exceptions extend the java.lang.RuntimeException.
3. There are many arguments for and against both checked and unchecked, and whether to use checked exceptions at all. I will go through the most common arguments throughout this text. Before I do so, let me just make one thing clear:
4. Checked and unchecked exceptions are functionally equivalent. There is nothing you can do with checked exceptions that cannot also be done with unchecked exceptions, and vice versa.
5. Regardless of your choice between checked and unchecked exceptions it is a matter of personal or organisational style. None is functionally better than the other.
A Simple Example
Before discussing the advantages and disadvantages of checked and unchecked exceptions I will show you the difference in the code they make. Here is a method that throws a checked exception, and another method that calls it:
public void storeDataFromUrl(String url){
try {
String data = readDataFromUrl(url);
} catch (BadUrlException e) {
e.printStackTrace();
}
}
public String readDataFromUrl(String url)
throws BadUrlException{
if(isUrlBad(url)){
throw new BadUrlException("Bad URL: " + url);
}
String data = null;
//read lots of data over HTTP and return
//it as a String instance.
return data;
}
As you can see the readDataFromUrl() method throws a BadUrlException. I have created BadUrlException myself. BadUrlException is a checked exception because it extends java.lang.Exception:
public class BadUrlException extends Exception {
public BadUrlException(String s) {
super(s);
}
}
If storeDataFromUrl() wants to call readDataFromUrl() it has only two choices. Either it catches the BadUrlException or propagates it up the call stack. The storeDataFromUrl() listed above catches the exception. This storeDataFromUrl() implementation propagates the BadUrlException instead:
public void storeDataFromUrl(String url)
throws BadUrlException{
String data = readDataFromUrl(url);
}
Notice how the try catch block is gone and a "throws BadUrlException" declaration is added instead. Now, let's see how it looks with unchecked exceptions. First I change the BadUrlException to extend java.lang.RuntimeException instead:
public class BadUrlException extends RuntimeException {
public BadUrlException(String s) {
super(s);
}
}
Then I change the methods to use the now unchecked BadUrlException:
public void storeDataFromUrl(String url){
String data = readDataFromUrl(url);
}
public String readDataFromUrl(String url) {
if(isUrlBad(url)){
throw new BadUrlException("Bad URL: " + url);
}
String data = null;
//read lots of data over HTTP and
//return it as a String instance.
return data;
}
Notice how the readDataFromUrl() method no longer declares that it throws BadUrlException. The storeDataFromUrl() method doesn't have to catch the BadUrlException either. The storeDataFromUrl() method can still choose to catch the exception but it no longer has to, and it no longer has to declare that it propagates the exception.

WHAT IS HARDWARE?

Information processing involves four phases: input, process, output, and storage. Each of these phases and the associated devices are discussed below.
Input devices: Input devices include the keyboard, pointing devices, scanners and reading devices, digital cameras, audio and video input devices, and input devices for physically challenged users. Input devices are used to capture data at the earliest possible point in the workflow, so that the data are accurate and readily available for processing.
Processing: After data are captured, they are processed. When data are processed, they are transformed from raw facts into meaningful information. A variety of processes may be performed on the data, such as adding, subtracting, dividing, multiplying, sorting, organizing, formatting, comparing, and graphing. After processing, information is output, as a printed report, for example, or stored as files.
Output devices: Four common types of output are text, graphics, audio, and video. Once information has been processed, it can be listened to through speakers or a headset, printed onto paper, or displayed on a monitor. An output device is any computer component capable of conveying information to a user. Commonly used output devices include display devices, printers, speakers, headsets, data projectors, fax machines, and multifunction devices. A multifunction device is a single piece of equipment that looks like a copy machine but provides the functionality of a printer, scanner, copy machine, and perhaps a fax machine.
Storage devices: Storage devices retain items such as data, instructions, and information for retrieval and future use. They include floppy disks or diskettes, hard disks, compact discs (both read-only and disc-recordable), tapes, PC cards, Smart Cards, microfilm, and microfiche.

INFORMATION and DATA PROCESSING INFORMATION TECHNOLOGY

Data processing is the input, verification, organization, storage, retrieval, transformation, and extraction of information from data. The term is usually associated with commercial applications such as inventory control or payroll. An information system refers to business applications of computers and consists of the databases, application programs, and manual and machine procedures and computer systems that process data. Databases store the master files of the business and its transaction files. Application programs provide the data entry, updating, and query and report processing. Manual procedures document the workflow, showing how the data are obtained for input and how the system's output is distributed. Machine procedures instruct the computers how to perform batch-processing activities, in which the output of one program is automatically fed into another program. Daily processing is the interactive, real-time processing of transactions. Batch-processing programs are run at the end of the day (or some other period) to update the master files that have not been updated since the last cycle. Reports are printed for the cycle's activities. Periodic processing of an information system involves updating of the master files— adding, deleting, and changing the information about customers, employees, vendors, and products.

WHAT IS SOFTWARE?

Computer software consists of the programs, or lists of instructions, that control the operation of a computer. Application software can be used for the following purposes:

• As a productivity/business tool
• To assist with graphics and multimedia projects
• To support household activities, for personal business, or for education
• To facilitate communications

Productivity Software Productivity software is designed to make people more effective and efficient when performing daily activities. It includes applications such as word processing, spreadsheets, databases, presentation graphics, personal information management, graphics and multimedia, communications, and other related types of software. Word-processing software is used to create documents such as letters, memos, reports, mailing labels, and newsletters. This software is used to create attractive and professional-looking documents that are stored electronically, allowing them to be retrieved and revised. The software provides tools to correct spelling and grammatical mistakes, permits copying and moving text without rekeying, and provides tools to enhance the format of documents. Electronic spreadsheet software is used in business environments to perform numeric calculations rapidly and accurately. Data are keyed into rows and columns on a worksheet, and formulas and functions are used to make fast and accurate calculations. Spreadsheets are used for "what-if" analyses and for creating charts based on information in a worksheet. A database is a collection of data organized in a manner that allows access, retrieval, and use of that data. A database management system (DBMS) is used to create a computerized database; add, change, and delete data; sort and retrieve data from the database; and create forms and reports using the data in the database. Presentation graphics software is used to create presentations, which can include clip-art images, pictures, video clips, and audio clips as well as text. A personal information manager is a software application that includes an appointment calendar, address book, and notepad to help organize personal information such as appointments and task lists. Engineers, architects, desktop publishers, and graphic artists often use graphics and multimedia software such as computer-aided design, desktop publishing, video and audio entertainment, and Web page authoring. Software for communications includes groupware, e-mail, and Web browsers.

INFORMATION TECHNOLOGY_TRENDS

Information Technology Departments will be increasingly concerned with data storage and management, and will find that information security will continue to be at the top of the priority list. Cloud computing remains a growing area to watch. The job outlook for those within Information Technology is strong, with data security and server gurus amongst the highest paid techies. Check out the Information Security Certifications and Highest Paying Certifications for more information. In order to stay current in the Information Technology Industry, be sure you subscribe to top technology industry publications.

INFORMATION TECHNOLOGY's ROLE NOW A DAY's

Every day, people use computers in new ways. Computers are increasingly affordable; they continue to be more powerful as information-processing tools as well as easier to use.
Computers in Business :One of the first and largest applications of computers is keeping and managing business and financial records. Most large companies keep the employment records of all their workers in large databases that are managed by computer programs. Similar programs and databases are used in such business functions as billing customers; tracking payments received and payments to be made; and tracking supplies needed and items produced, stored, shipped, and sold. In fact, practically all the information companies need to do business involves the use of computers and information technology.
On a smaller scale, many businesses have replaced cash registers with point-of-sale (POS) terminals. These POS terminals not only print a sales receipt for the customer but also send information to a computer database when each item is sold to maintain an inventory of items on hand and items to be ordered. Computers have also become very important in modern factories. Computer-controlled robots now do tasks that are hot, heavy, or hazardous. Robots are also used to do routine, repetitive tasks in which boredom or fatigue can lead to poor quality work.
Computers in Medicine: Information technology plays an important role in medicine. For example, a scanner takes a series of pictures of the body by means of computerized axial tomography (CAT) or magnetic resonance imaging (MRI). A computer then combines the pictures to produce detailed three-dimensional images of the body's organs. In addition, the MRI produces images that show changes in body chemistry and blood flow.
Computers in Science and Engineering: Using supercomputers, meteorologists predict future weather by using a combination of observations of weather conditions from many sources, a mathematical representation of the behavior of the atmosphere, and geographic data.
Computer-aided design and computer-aided manufacturing programs, often called CAD/CAM, have led to improved products in many fields, especially where designs tend to be very detailed. Computer programs make it possible for engineers to analyze designs of complex structures such as power plants and space stations.
Integrated Information Systems: With today's sophisticated hardware, software, and communications technologies, it is often difficult to classify a system as belonging uniquely to one specific application program. Organizations increasingly are consolidating their information needs into a single, integrated information system. One example is SAP, a German software package that runs on mainframe computers and provides an enterprise-wide solution for information technologies. It is a powerful database that enables companies to organize all their data into a single database, then choose only the program modules or tables they want. The freestanding modules are customized to fit each customer's needs.

MOST POPULAR INFORMATION TECHNOLOGY SKILLS

Some of the most popular information technology skills at the moment are:

• Computer Networking
• Information Security
• IT Governance
• ITIL
• Business Intelligence
• Linux
• Unix
• Project Management

MODERN INFORMATION TECHNOLOGY

In order to perform the complex functions required of information technology departments today, the modern Information Technology Department would use computers, servers, database management systems, and cryptography. The department would be made up of several System Administrators, Database Administrators and at least one Information Technology Manager. The group usually reports to the Chief Information Officer (CIO).

HISTORY OF INFORMATION TECHNOLOGY

The term "information technology" evolved in the 1970s. Its basic concept, however, can be traced to the World War II alliance of the military and industry in the development of electronics, computers, and information theory. After the 1940s, the military remained the major source of research and development funding for the expansion of automation to replace manpower with machine power.
Since the 1950s, four generations of computers have evolved. Each generation reflected a change to hardware of decreased size but increased capabilities to control computer operations. The first generation used vacuum tubes, the second used transistors, the third used integrated circuits, and the fourth used integrated circuits on a single computer chip. Advances in artificial intelligence that will minimize the need for complex programming characterize the fifth generation of computers, still in the experimental stage.
The first commercial computer was the UNIVAC I, developed by John Eckert and John W. Mauchly in 1951. It was used by the Census Bureau to predict the outcome of the 1952 presidential election. For the next twenty-five years, mainframe computers were used in large corporations to do calculations and manipulate large amounts of information stored in databases. Supercomputers were used in science and engineering, for designing aircraft and nuclear reactors, and for predicting worldwide weather patterns. Minicomputers came on to the scene in the early 1980s in small businesses, manufacturing plants, and factories.
In 1975, the Massachusetts Institute of Technology developed microcomputers. In 1976, Tandy Corporation's first Radio Shack microcomputer followed; the Apple microcomputer was introduced in 1977. The market for microcomputers increased dramatically when IBM introduced the first personal computer in the fall of 1981. Because of dramatic improvements in computer components and manufacturing, personal computers today do more than the largest computers of the mid-1960s at about a thousandth of the cost.
Computers today are divided into four categories by size, cost, and processing ability. They are supercomputer, mainframe, minicomputer, and microcomputer, more commonly known as a personal computer. Personal computer categories include desktop, network, laptop, and handheld.

DEFINATION OF INFORMATION TECHNOLOGY

Information technology, as defined by the Information Technology Association of America
(ITAA), is "the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware." Encompassing the computer and information systems industries, information technology is the capability to electronically input, process, store, output, transmit, and receive data and information, including text, graphics, sound, and video, as well as the ability to control machines of all kinds electronically.
Information technology is comprised of computers, networks, satellite communications, robotics, videotext, cable television, electronic mail ("e-mail"), electronic games, and automated office equipment. The information industry consists of all computer, communications, and electronics-related organizations, including hardware, software, and services. Completing tasks using information technology results in rapid processing and information mobility, as well as improved reliability and integrity of processed information

INTERFACE MEANS?

DEFINTION: Well, I am a self-learn programmer. If you are a beginer, I believe you will get headache like me when you read tutorial written by experienced programmer explaining "interface" with professional words.
If you are beginner, I believe you will get more help from a tutorial written by a non-professional programmer like me.
So, what is inteface ? Like others, I will explain it by examples.
We have various shapes. Square, triangle and circle. There are many common porperties among them. Like, color,rotation, x,y etc. So, we can create a "Shape" class with methods as getColor(), getRotation()......etc.
After we have Shape Class, we start our jobs. Now, we need to create Square class, Circle class and Triangle class. Well, it is simple. Make Square class extends Shape, so Square class will inherit all those methods in Shape. Most of these methods like getColor(), getRotation()... etc, do not need additional codes. We use these methods defined in its Ancestor "Shape" class. We dont need any codes before we can use them. At most, we need small modification only. So does the Circle and Triangle class.
Now, we face another set of "common" methods. We need a method to show the area of the shape. Unlike the function getColor(), the formula to calculate area of square, circle or triangle are totally different from each other. It is impossible to write a general function in the "Shape" class to calculate the area. Thus, although we need a "common" function to show the area of various shape, in fact, there is nothing in common.
For example,
in class Square, we have getRectArea(){return (height*width);};
in class Circle, we have getCircleArea(){return (radius*Math.PI*Math.PI);};
in class Triangle, we have getTriangleArea(){return (height*widht/2);};
OK, that goes without any problems. But, are'nt they all serve as a method to calculate Area ? Good programmer will try to give all these methods the same name - for example "getArea". Other wise, we need Square.getRectArea() to know the area. Circle.getCircleArea() to know the area and Triangle.getTriangleArea() to get the area of triangle instance. Although the formula is different, a common method name means they function the same goal. And, that make them more like "the same kind" of thing.
Here comes the interface.
interface RegularShape
{
    var getArea();
 }
Lets modify our class Circle by :
class Circle extends Shape implements RegularShape{
......
}
After click "check syntax", Flash complains that, we should have a "getArea()" method.
So, we are hint, and we follow the hint. We rename our "getCircleArea" method to "getArea" method. Thus, we use getArea to get the area of a Circle instance instead of getCircleArea();
Also, we implements RegularShape to Square class. And we are forced to rename our getRectArea into getArea(). Same things happen to our Triangle class.
That is all about interface.

DBMS MEAN'S

DEFINATION:A collection of programs that enables you to store, modify, and extract information from a database. There are many different types of DBMSs, ranging from small systems that run on personal computers to huge systems that run on mainframes.
 The following are examples of database applications:
computerized library systems
automated teller machines
flight reservation systems
computerized parts inventory systems
From a technical standpoint, DBMSs can differ widely. The terms relational, network, flat, and hierarchical all refer to the way a DBMS organizes information internally. The internal organization can affect how quickly and flexibly you can extract information.
Requests for information from a database are made in the form of a query, which is a stylized question. For example, the query
SELECT ALL WHERE NAME = "SMITH" AND AGE > 35
requests all records in which the NAME field is SMITH and the AGE field is greater than 35. The set of rules for constructing queries is known as a query language. Different DBMSs support different query languages, although there is a semi-standardized query language called SQL (structured query language). Sophisticated languages for managing database systems are called fourth-generation languages, or 4GLs for short.
The information from a database can be presented in a variety of formats. Most DBMSs include a report writer program that enables you to output data in the form of a report. Many DBMSs also include a graphics component that enables you to output information in the form of graphs and charts.

WHAT IS MEAN BY THREAD

DEFINATION- 1) On the Internet in Usenet newsgroups and similar forums, a thread is a sequence of responses to an initial message posting. This enables you to follow or join an individual discussion in a newsgroup from among the many that may be there. A thread is usually shown graphically as an inital message and successive messages "hung off" the original message. As a newsgroup user, you contribute to a thread by specifying a "Reference" topic as part of your message.
2) In computer programming, a thread is placeholder information associated with a single use of a program that can handle multiple concurrent users. From the program's point-of-view, a thread is the information needed to serve one individual user or a particular service request. If multiple users are using the program or concurrent requests from other programs occur, a thread is created and maintained for each of them. The thread allows a program to know which user is being served as the program alternately gets re-entered on behalf of different users. (One way thread information is kept by storing it in a special data area and putting the address of that data area in a register. The operating system always saves the contents of the register when the program is interrupted and restores it when it gives the program control again.)
A thread and a task are similar and are often confused. Most computers can only execute one program instruction at a time, but because they operate so fast, they appear to run many programs and serve many users simultaneously. The computer operating system gives each program a "turn" at running, then requires it to wait while another program gets a turn. Each of these programs is viewed by the operating system as a task for which certain resources are identified and kept track of. The operating system manages each application program in your PC system (spreadsheet, word processor, Web browser) as a separate task and lets you look at and control items on a task list. If the program initiates an I/O request, such as reading a file or writing to a printer, it creates a thread. The data kept as part of a thread allows a program to be reentered at the right place when the I/O operation completes. Meanwhile, other concurrent uses of the program are maintained on other threads. Most of today's operating systems provide support for both multitasking and multithreading. They also allow multithreading within program processes so that the system is saved the overhead of creating a new process for each thread.
The POSIX.4a C specification provides a set of application program interfaces that allow a programmer to include thread support in the program. Higher-level program development tools and application subsystems and middleware also offer thread management facilities. Languages that support object-oriented programming also accommodate and encourage multithreading in several ways. Java supports multithreading by including synchronization modifiers in the language syntax, by providing classes developed for multithreading that can be inherited by other classes, and by doing background "garbage collection" (recovering data areas that are no longer being used) for multiple threads.