FTP Protocol full Study in Details

                              Protocols

Introduction
One of the most popular user of the internet is to download File .... that is transfer file from a computer on the internet to your computer. many thousands of files are downloaded easy day from the internet. Most of these file are downloaded using the internet file Transfer Protocol commonly referred to a FTP . This Protocol can also be used for uplode file from your computer  to another computer on the internet


FTP (File Transfer Protocol)
FTP is a Standard Network Protocol Use to Exchange and Manipulate File over a TCP/IP- based network such as a Internet. FTP built on a client server architecture and utlize separate control and dataconnection between the client and server application FTP is used with the user based Password authenticationor with anonymous uiser access. Application Were Originally interactive command Lines tool with standardized command suyntax But graphical user interfaceshave been developed for all operating sysytem in use Today . The trivial File Tranfer Protocol(TFTP) is a Similar, simplified interoperable and unanthenticated verison of FTP.

Actualy the FTP is an intractive system. The FTP client that cames with windows NT or 2000 is a character-based client.
FTP execute  on top of TCP/IP stack and uses the OSI protocol to enable users and application to transfer files among networked station.

FTP Server 
                          a) Anonymous server
                          b) Anonymous server

a) Anonymous server :- It is the most common use of FTP,the internet file transfer protocol. FTP sites that allow anonymous FTP do not require a password for access. you only have to log in as anonymous and enter you email address as password ( for their records).
b) Non Anonymous server :- If you use a non anonymous server, then you will log in as yourselfand give your password.

FTP Clients
FTP runs on a client/ server model. For using FTP you will need client software to run on PC.
To begin an FTP sssion you run the FTP Client Software and contant the FTP server from ware you want to download file from. you can use FTP client software available windows 2000. thr FTP client talks to a FTP server. FTP uses TCP to handel communicationand create a session betwoon the two hosts.
The FTP daemon runs on FTP server. The Daemon handlee all FTP transaction . When an FTP clint contects a server a daemon will ask for an account number (or user name) and password many FTP sites allow anonymous FTP an explained earlier.
some FTP clients will automatically log on to the FTP server for you when you connect so you will not be asked to log on. It is so because your clients software does it automatically for you.
If you issue a command to download a file , a second connection is opened up called the data connection or data link. This connection can be opened up in one of the following two modes:

* ASCLL Mode
* Binary Mode
* Line Mode

1) ASCII Mode : It is used for sending text files and alters thing such as line feed and carringe                                        returns.
2) Binary Mode: It is used for sending Binary files and lets files through untouched.
3) Line Mode    : It is use to send text files line by line or it is similar to ASCII mode but with                                          aditional features.

Connecting with FTP 
Typical FTP session stset as client, when you the FTP Program and connect to an FTP site, sending on the program you have , you will ? enter you login information before connect or you will be prompted to do it after you connect if you are using web brouser to connect to another site, The Brouser will Prompt you to connect to an FTP site; you need to know the IP of an account on the FTP server  . In other Is, you need to login with a user name and password so that the server know who you are. y accessible FTP sites expect you to use a account called anonymous . unless you spec-, Internet Explorer assumes that you want to con-to FTP sites as an anonymous user . and it supplies the server withe the user name anonymous and a password consisting of your own email address.

To connect to an FTP site do this :
1) Enter the URL of the FTP site in the address box and click Go. for Example ,to connect to FTP site rtfm.mit.edu/pub/  enter the URL as follows:
   ftp://rtfm.mtf.edu/pub/
2) The browser open the specified site.
3) Display the directory that contans the file you want to download.
4) Right click the file and choose copy to folder.
5) Once you have saved the file in computer drive , you can open it using the appropriate software, depending upon the type of file. if it is a doc file,    you can use microsoft word  to open this file.

FTP Common Command:
* The basic command is :
  1) FTP Hostname : This command is written at the Doc Prompt and its opens and intractive FTP session. when you want to run FTP in a script, the available      switches are as follows: ftp[-v] [-d] [-i] [-n] [-g] [-s:filename] [-a] [-w:windowsize] [computer] summarizes the parameters that you can enter he      command.
     Most of the time, you use the FTP client in intrective mode. you should be aware of saveral command when you are in this mode.

GUI(graphical user interface) Based FTP Clients:

* WS_FTP Client : WS_FTP has been available for several years, but it is still one of the best FTP        Client arround.the FTP client is free to gornment and   acadmic uses and to individual also for their    non-commercial use to get a latest version os WS_FTP from the following web site, type:
   http://ipswitch.com/Product/WS_FTP/index.html

Browser Based FTP Clients
* FTP With Internet Explorer: Microsoft internet explorer FTP interface is based on the ordinary           Window Explorer folder, which makes remote file access as easy as accessing folder on your owr        Computer.

-> Follow the steps:-
    1) Activate Internet Explorer By clicking its desktop shortcut or by clicking the start and choose program and the choose internet explorer.
    2) connectly to a site directly by entring its address in the address box such as the following:
        ftp://ftp.microsoft.com  or
        ftp://your_username :your_password@ ftp.your_ISP.com)
    3) To navigate the FTP site, click folder icon to open subsirectories.
    4) Click on the file to download them.
    5) Exit internet Explorer by selecting file and then choose close.

you will be prompted to disconnect from your internet service provider (ISP).

Please read next topic in next post....Thank You So Much...
   

 



Facebook Details


                                                        FACEBOOK


Facebook (stylized as facebook) is a for-profit corporation and online social networking service based in Menlo Park, California, United States. The Facebook website was launched on February 4, 2004, by Mark Zuckerberg, along with fellow Harvard College students and roommates, Eduardo Saverin, Andrew McCollum, Dustin Moskovitz, and Chris Hughes.

Facebook is a popular free social networking website that allows registered users to create profiles, upload photos and video, send messages and keep in touch with friends, family and colleagues. The site, which is available in 37 different languages, includes public features such .
facebook logo
The founders had initially limited the website's membership to Harvard students; however, later they expanded it to higher education institutions in the Boston area, the Ivy League schools, and Stanford University. Facebook gradually added support for students at various other universities, and eventually to high school students as well. Since 2006, anyone age 13 and older has been allowed to become a registered user of Facebook, though variations exist in the minimum age requirement, depending on applicable local laws. The Facebook name comes from the face book directories often given to United States university students.
After registering to use the site, users can create a user profile, add other users as "friends", exchange messages, post status updates and photos, share videos, use various applications (apps), and receive notifications when others update their profiles. Additionally, users may join common-interest user groups organized by workplace, school, or other topics, and categorize their friends into lists such as "People From Work" or "Close Friends". In groups, editors can pin posts to top. Additionally, users can complain about or block unpleasant people. Because of the large volume of data that users submit to the service, Facebook has come under scrutiny for its privacy policies.
facebook Home Page


Facebook, Inc. held its initial public offering (IPO) in February 2012, and began selling stock to the public three months later, reaching an original peak market capitalization of $104 billion. On July 13, 2015, Facebook became the fastest company in the Standard & Poor's 500 Index to reach a market cap of $250 billion. Facebook has more than 1.65 billion monthly active users as of March 31, 2016.


History

History of Facebook and Timeline of Facebook
2003–2006: Thefacebook, Thiel investment, and name change

Zuckerberg wrote a program called "Facemash" on October 28, 2003 while attending Harvard University as a sophomore (second year student). According to The Harvard Crimson, the site was comparable to Hot or Not and used "photos compiled from the online facebooks of nine houses, placing two next to each other at a time and asking users to choose the 'hotter' person".

To accomplish this, Zuckerberg hacked into protected areas of Harvard's computer network and copied private dormitory ID images. Harvard did not have a student "face book" (a directory with photos and basic information) at the time, although individual houses had been issuing their own paper facebooks since the mid-1980s, and Harvard's longtime Freshman Yearbook was colloquially referred to as the "Freshman Facebook". Facemash attracted 450 visitors and 22,000 photo-views in its first four hours online.

The site was quickly forwarded to several campus group list-servers, but was shut down a few days later by the Harvard administration. Zuckerberg faced expulsion and was charged by the administration with breach of security, violating copyrights, and violating individual privacy. Ultimately, the charges were dropped.[18] Zuckerberg expanded on this initial project that semester by creating a social study tool ahead of an art history final exam. He uploaded 500 Augustan images to a website, each of which was featured with a corresponding comments section. He shared the site with his classmates, and people started sharing notes.
Original layout and name of Thefacebook, 2004.

The following semester, Zuckerberg began writing code for a new website in January 2004. He said that he was inspired by an editorial about the Facemash incident in The Harvard Crimson. On February 4, 2004, Zuckerberg launched "Thefacebook", originally located at thefacebook.com.

Six days after the site launched, Harvard seniors Cameron Winklevoss, Tyler Winklevoss, and Divya Narendra accused Zuckerberg of intentionally misleading them into believing that he would help them build a social network called HarvardConnection.com. They claimed that he was instead using their ideas to build a competing product. The three complained to The Harvard Crimson and the newspaper began an investigation. They later filed a lawsuit against Zuckerberg, subsequently settling in 2008  for 1.2 million shares (worth $300 million at Facebook's IPO)

Membership was initially restricted to students of Harvard College; within the first month, more than half the undergraduates at Harvard were registered on the service. Eduardo Saverin (business aspects), Dustin Moskovitz (programmer), Andrew McCollum (graphic artist), and Chris Hughes joined Zuckerberg to help promote the website. In March 2004, Facebook expanded to the universities of Columbia, Stanford, and Yale. It later opened to all Ivy League colleges, Boston University, New York University, MIT, and gradually most universities in the United States and Canada.

In mid-2004, entrepreneur Sean Parker—an informal advisor to Zuckerberg—became the company's president.[28] In June 2004, Facebook moved its operations base to Palo Alto, California. It received its first investment later that month from PayPal co-founder Peter Thiel. In 2005, the company dropped "the" from its name after purchasing the domain name facebook.com for US$200,000. The domain facebook.com belonged to AboutFace Corporation before the purchase. This website last appeared on April 8, 2005; from April 10, 2005 to August 4, 2005, this domain gave a 403 error.

Mark Zuckerberg, co-creator of Facebook, in his Harvard dorm room, 2005.
In May 2005, Accel Partners invested $12.7 million in Facebook, and Jim Breyer  added $1 million of his own money. A high-school version of the site was launched in September 2005, which Zuckerberg called the next logical step.  (At the time, high-school networks required an invitation to join.)  Facebook also expanded membership eligibility to employees of several companies, including Apple Inc. and Microsoft.


2006–2012: public access, Microsoft alliance and rapid growth
On September 26, 2006, Facebook was opened to everyone at least 13 years old with a valid email address. In late 2007, Facebook had 100,000 business pages (pages which allowed companies to promote themselves and attract customers). These started as group pages, but a new concept called company pages was planned.[40] Pages began rolling out for businesses in May 2009.
On October 24, 2007, Microsoft announced that it had purchased a 1.6% share of Facebook for $240 million, giving Facebook a total implied value of around $15 billion. Microsoft's purchase included rights to place international advertisements on the social networking site.

In October 2008, Facebook announced that it would set up its international headquarters in Dublin, Ireland. Almost a year later, in September 2009, Facebook said that it had turned cash-flow positive for the first time.
A January 2009 Compete.com study ranked Facebook the most used social networking service by worldwide monthly active users. Entertainment Weekly included the site on its end-of-the-decade "best-of" list saying, "How on earth did we stalk our exes, remember our co-workers' birthdays, bug our friends, and play a rousing game of Scrabulous before Facebook?"

Traffic to Facebook increased steadily after 2009. The company announced 500 million users in July 2010 . making it the largest online social network in the world at the time. According to the company's data, half of the site's membership use Facebook daily, for an average of 34 minutes, while 150 million users access the site by mobile. A company representative called the milestone a "quiet revolution."
In November 2010, based on SecondMarket Inc. (an exchange for privately held companies' shares), Facebook's value was $41 billion. The company had slightly surpassed eBay to become the third largest American web company after Google and Amazon.com.

Facebook headquarters entrance sign at 1 Hacker Way, Menlo Park, California
In early 2011, Facebook announced plans to move its headquarters to the former Sun Microsystems campus in Menlo Park, California. In March 2011, it was reported that Facebook was removing approximately 20,000 profiles offline every day for violations such as spam, graphic content, and underage use, as part of its efforts to boost cyber security. Release of statistics by DoubleClick showed that Facebook reached one trillion page views in the month of June 2011, making it the most visited website tracked by DoubleClick. According to a Nielsen Media Research study, released in December 2011, Facebook had become the second-most accessed website in the U.S. behind Google.


2012–2013: IPO, lawsuits and one-billionth user
Initial public offering of Facebook
Facebook eventually filed for an initial public offering on February 1, 2012. Facebook held an initial public offering on May 17, 2012, negotiating a share price of US$38. The company was valued at $104 billion, the largest valuation to date for a newly listed public company.


Facebook Inc. began selling stock to the public and trading on the NASDAQ on May 18, 2012.[60] Based on its 2012 income of $5 billion, Facebook joined the Fortune 500 list for the first time in May 2013, ranked in position 462.
Facebook filed their S1 document with the Securities and Exchange Commission on February 1, 2012. The company applied for a $5 billion IPO, one of the biggest offerings in the history of technology. The IPO raised $16 billion, making it the third-largest in U.S. history.

The shares began trading on May 18; the stock struggled to stay above the IPO price for most of the day, but set a record for the trading volume of an IPO (460 million shares). The first day of trading was marred by technical glitches that prevented orders from going through; only the technical problems and artificial support from underwriters prevented the stock price from falling below the IPO price on the day.
In March 2012, Facebook announced App Center, a store selling applications that operate via the site. The store was to be available on iPhones, Android devices, and mobile web users.
Billboard on the Thomson Reuters building welcomes Facebook to NASDAQ, 2012 .On May 22, 2012, the Yahoo! Finance website reported that Facebook's lead underwriters, Morgan Stanley (MS), JP Morgan (JPM), and Goldman Sachs (GS), cut their earnings forecasts for the company in the middle of the IPO process. The stock had begun its freefall by this time, closing at 34.03 on May 21 and 31.00 on May 22. A "circuit breaker" was used in an attempt to slow down the stock price's decline. Securities and Exchange Commission Chairman Mary Schapiro, and Financial Industry Regulatory Authority (FINRA) Chairman Rick Ketchum, called for a review of the circumstances surrounding the IPO.

Facebook's IPO was consequently investigated, and was compared to a pump and dump scheme. A class-action lawsuit was filed in May 2012 because of the trading glitches, which led to botched orders. Lawsuits were filed, alleging that an underwriter for Morgan Stanley selectively revealed adjusted earnings estimates to preferred clients.
The other underwriters (MS, JPM, GS), Facebook's CEO and board, and NASDAQ also faced litigation after numerous lawsuits were filed, while SEC and FINRA both launched investigations. It was believed that adjustments to earnings estimates were communicated to the underwriters by a Facebook financial officer, who used the information to cash out on their positions while leaving the general public with overpriced shares. By the end of May 2012, Facebook's stock lost over a quarter of its starting value, which led the Wall Street Journal to label the IPO a "fiasco".
Zuckerberg announced to the media at the start of October 2012 that Facebook had passed the monthly active users mark of one billion -Facebook defines active users as a logged-in member who visits the site, or accesses it through a third-party site connected to Facebook, at least once a month. Fake accounts were not mentioned in the announcement, but the company continued to remove them after it found that 8.7% of its users were not real in August 2012. The company's data also revealed 600 million mobile users, 140 billion friend connections since the inception of Facebook, and the median age of a user as 22 years.

Following a campaign by 100 advocacy groups, Facebook agreed to update its policy on hate speech. The campaign highlighted content promoting domestic and sexual violence against women, and used over 57,000 tweets and more than 4,900 emails that caused withdrawal of advertising from the site by 15 companies, including Nissan UK, House of Burlesque and Nationwide UK. The social media website initially responded by stating that "while it may be vulgar and offensive, distasteful content on its own does not violate our policies". It decided to take action on May 29, 2013, after it "become clear that our systems to identify and remove hate speech have failed to work as effectively as we would like, particularly around issues of gender-based hate."On June 12, 2013, Facebook announced on its newsroom that it was introducing clickable hashtags to help users follow trending discus

United States

Facebook's role in the American political process was demonstrated in January 2008, shortly before the New Hampshire primary, when Facebook teamed up with ABC and Saint Anselm College to allow users to give live feedback about the "back to back" January 5 Republican and Democratic debates. Facebook users took part in debate groups organized around specific topics, register to vote, and message questions.
Over a million people installed the Facebook application "US Politics on Facebook" in order to take part, and the application measured users' responses to specific comments made by the debating candidates. This debate showed the broader community what many young students had already experienced: Facebook as a popular and powerful new way to interact and voice opinions. A poll by CBS News,UWIRE

United States

Facebook's role in the American political process was demonstrated in January 2008, shortly before the New Hampshire primary, when Facebook teamed up with ABC and Saint Anselm College to allow users to give live feedback about the "back to back" January 5 Republican and Democratic debates. Facebook users took part in debate groups organized around specific topics, register to vote, and message questions.
Over a million people installed the Facebook application "US Politics on Facebook" in order to take part, and the application measured users' responses to specific comments made by the debating candidates. This debate showed the broader community what many young students had already experienced: Facebook as a popular and powerful new way to interact and voice opinions. A poll by CBS News,UWIRE and The Chronicle of Higher Education claimed to illustrate how the "Facebook effect" has affected youth voting rates, support by youth of political candidates, and general involvement by the youth population in the 2008 election.
The new social media, such as Facebook and Twitter, made use first of the personal computer and the Internet, and after 2010 of the smart phones to connect hundreds of millions of people, especially those under age 35. By 2008, politicians and interest groups were experimenting with systematic use of social media to spread their message among much larger audiences than they had previously reached.
Facebook is having an impact on local government as well. Justin Smith, a Colorado sheriff uses Facebook to disseminate his ideas on matters relating to local, state, and national concerns. He also publicizes crimes, particularly those that his department solves. He has seven thousand followers on the social medium, considered a large number. Smith said that he rarely goes out in public "when I don't get feedback from folks. … Facebook is an interesting tool because I think it holds candidates and elected officials more accountable. Voters know where someone stands."
As American political strategists turn their attention to the 2016 presidential contest, they identify Facebook as an increasingly important advertising tool. Recent technical innovations have made possible more advanced divisions and subdivisions of the electorate. Most important, Facebook can now deliver video ads to small, highly targeted subsets. Television, by contrast, shows the same commercials to all viewers, and so cannot be precisely tailored.

Ban

In many countries the social networking sites and mobile apps have been blocked temporarily or permanently. In Bangladesh, the government has been blocking Facebook, WhatsApp, Tango, Viber and many other sites and apps since November 18, 2015.

In popular culture




  • American author Ben Mezrichpublished a book in July 2009 about Zuckerberg and the founding of Facebook, titled The Accidental Billionaires: The Founding of Facebook, A Tale of Sex, Money, Genius, and Betrayal.
  • The Social Network, a drama film directed by David Fincher and adapted from Mezrich's book, was released October 1, 2010.
  •  People portrayed in the movie, including Zuckerberg, have criticized its accuracy. However a search ofIMDB will reveal this to be a movie produced as standard entertainment.
  • In response to the Everybody Draw Mohammed Day controversy and the banning of the website in Pakistan, an Islamic version of the website was created, called MillatFacebook.
  • "You Have 0 Friends", an April 2010 episode of the American animated comedy series, South Park, explicitly parodied Facebook.
  • At age 102, Ivy Bean of Bradford, England joined Facebook in 2008, making her one of the oldest people ever on Facebook.
  •  At the time of her death in July 2010, she had 4,962 friends on Facebook and more than 56,000 followers on Twitter.
  • On May 16, 2011, an Israeli couple named their daughter after the Facebook "like" feature.
  • In July 2014, Shakira became the first celebrity to cross over 100 million likes,Cristiano Ronaldo is the second to reach 100 million likes, ahead ofRihanna and Eminem, who had 98 million and 89 million likes respectively. Mark Zuckerberg posted a congratulatory message on the artist's wall

  •  and The Chronicle of Higher Education claimed to illustrate how the "Facebook effect" has affected youth voting rates, support by youth of political candidates, and general involvement by the youth population in the 2008 election.
    The new social media, such as Facebook and Twitter, made use first of the personal computer and the Internet, and after 2010 of the smart phones to connect hundreds of millions of people, especially those under age 35. By 2008, politicians and interest groups were experimenting with systematic use of social media to spread their message among much larger audiences than they had previously reached.
    Facebook is having an impact on local government as well. Justin Smith, a Colorado sheriff uses Facebook to disseminate his ideas on matters relating to local, state, and national concerns. He also publicizes crimes, particularly those that his department solves. He has seven thousand followers on the social medium, considered a large number. Smith said that he rarely goes out in public "when I don't get feedback from folks. … Facebook is an interesting tool because I think it holds candidates and elected officials more accountable. Voters know where someone stands. As American political strategists turn their attention to the 2016 presidential contest, they identify Facebook as an increasingly important advertising tool. Recent technical innovations have made possible more advanced divisions and subdivisions of the electorate. Most important, Facebook can now deliver video ads to small, highly targeted subsets. Television, by contrast, shows the same commercials to all viewers, and so cannot be precisely tailored.

    Ban

    In many countries the social networking sites and mobile apps have been blocked temporarily or permanently. In Bangladesh, the government has been blocking Facebook, WhatsApp, Tango, Viber and many other sites and apps since November 18, 2015.

    In popular culture

    • American author Ben Mezrichpublished a book in July 2009 about Zuckerberg and the founding of Facebook, titled The Accidental Billionaires: The Founding of Facebook, A Tale of Sex, Money, Genius, and Betrayal.
    • The Social Network, a drama film directed by David Fincher and adapted from Mezrich's book, was released October 1, 2010.People portrayed in the movie, including Zuckerberg, have criticized its accuracy. However a search ofIMDB will reveal this to be a movie produced as standard entertainment.
    • In response to the Everybody Draw Mohammed Day controversy and the banning of the website in Pakistan, an Islamic version of the website was created, called MillatFacebook.
    • "You Have 0 Friends", an April 2010 episode of the American animated comedy series, South Park, explicitly parodied Facebook.
    • At age 102, Ivy Bean of Bradford, England joined Facebook in 2008, making her one of the oldest people ever on Facebook. At the time of her death in July 2010, she had 4,962 friends on Facebook and more than 56,000 followers on Twitter.
    • On May 16, 2011, an Israeli couple named their daughter after the Facebook "like" feature.

    A July 2013 Wall Street Journal article identified the Facebook IPO as the cause of a change in the U.S.' national economic statistics, as the local government area of the company's headquarters, San Mateo County, California, became the top wage-earning county in the country after the fourth quarter of 2012. The Bureau of Labor Statistics reported that the average weekly wage in the county was US$3,240, 107% higher than the previous year. It noted the wages were "the equivalent of $168,000 a year, and more than 50% higher than the next-highest county, New York County (better known as Manhattan), at $2,107 a week, or roughly $110,000 a year." Russian internet firm Mail.Ru sold its Facebook shares for US$525 million on September 5, 2013, following its initial $200 million investment in 2009. Partly owned by Russia's richest man, Alisher Usmanovhe, the firm owned a total of 14.2 million remaining shares prior to the sale. In the same month, the Chinese government announced that it will lift the ban on Facebook in the Shanghai Free Trade Zone "to welcome foreign companies to invest and to let foreigners live and work happily in the free-trade zone." Facebook was first blocked in China in 2009. Facebook was announced as a member of The Alliance for Affordable Internet (A4AI) in October 2013, when the A4AI was launched. The A4AI is a coalition of public and private organisations that includes Google, Intel and Microsoft. Led by Sir Tim Berners-Lee, the A4AI seeks to make Internet access more affordable so that access is broadened in the developing world, where only 31% of people are online. Google will help to decrease Internet access prices so that they fall below the UN Broadband Commission's worldwide target of 5% of monthly income.


    A Reuters report, published on December 11, 2013, stated that Standard & Poor's announced the placement of Facebook on its S&P 500 index "after the close of trading on December 20."[94] Facebook announced Q4 2013 earnings of $523 million (20 cents per share), an increase of $64 million from the previous year,[95] as well as 945 million mobile users. By January 2014, Facebook's market capitalization had risen to over $134 billion. At the end of January 2014, 1.23 billion users were active on the website every month. The company celebrated its 10th anniversary during the week of February 3, 2014.In each of the first three months of 2014, over one billion users logged into their Facebook account on a mobile device. In February 2014, Facebook announced that it would be buying mobile messaging company Whatsapp for US$19 billion in cash and stock. In June 2014, Facebook announced the acquisition of Pryte, a Finnish mobile data-plan firm that aims to make it easier for mobile phone users in underdeveloped parts of the world to use wireless Internet apps. At the start of July 2014, Facebook announced the acquisition of LiveRail, a San Francisco, California-based online video advertising company. LiveRail's technology facilitates the sale of video inventory across different devices. The terms of the deal were undisclosed, but TechCrunch reported that Facebook paid between US$400 million and $500 million. As part of the company's second quarter results, Facebook announced in late July 2014 that mobile accounted for 62% of its advertising revenue, which is an increase of 21% from the previous year.
    Alongside other American technology figures like Jeff Bezos and Tim Cook, Zuckerberg hosted visiting Chinese politician Lu Wei, known as the "Internet czar" for his influence in the enforcement of China's online policy, at Facebook's headquarters on December 8, 2014. The meeting occurred after Zuckerberg participated in a Q&A session at Tsinghua University in Beijing, China, on October 23, 2014, where he attempted to converse in Mandarin—although Facebook is banned in China, Zuckerberg is highly regarded among the people and was at the university to help fuel the nation's burgeoning entrepreneur sector. A book of Chinese president Xi Xinping found on Zuckerberg's office desk attracted a great deal of attention in the media, after the Facebook founder explained to Lu, "I want them [Facebook staff] to understand socialism with Chinese characteristics."
    Zuckerberg fielded questions during a live Q&A session at the company's headquarters in Menlo Park on December 11, 2014. The question of whether the platform would adopt a dislike button was raised again, and Zuckerberg said, "We're [Facebook] thinking about it [dislike button] … It's an interesting question," and said that he likes the idea of Facebook users being able to express a greater variety of emotions. In October 2015, Zuckerberg said that instead of creating a dislike button, Facebook is testing emoji reactions as an alternative to the 'like' button. On February 24, 2016, Facebook launched Facebook Reactions, which allows users to respond to posts with multiple reactions in addition to "liking" it.
    As of January 21, 2015, Facebook's algorithm is programmed to filter out false or misleading content, such as fake news stories and hoaxes, and will be supported by users who select the option to flag a story as "purposefully fake or deceitful news." According to Reuters, such content is "being spread like a wildfire" on the social media platform. Facebook maintained that "satirical" content, "intended to be humorous, or content that is clearly labeled as satire," will be taken into account and should not be intercepted. The algorithm, however, has been accused of maintaining a "filter bubble", where both material the user disagrees with[111] and posts with a low level of likes, will also not be seen. In 2015 November, Zuckerberg prolonged period of paternity leave from 4 weeks to 4 months.
    On April 12, 2016, Zuckerberg revealed a decade-long plan for Facebook in a keynote address. His speech outlined his vision, which was centered around three main pillars: artificial intelligence, increased connectivity around the world and virtual and augmented reality. He also announced a new Facebook Messenger platform, which will have developers creating bots that are able to engage in automatic interactions with customers. In June 2016 Facebook announced Deep Text, a natural language processing AI which will learn user intent and context in 20 languages.
    On May 31, 2016, Facebook, along with Google, Microsoft, and Twitter, jointly agreed to a European Union code of conduct obligating them to review "[the] majority of valid notifications for removal of illegal hate speech" posted on their services within 24 hours. Facebook introduced 360-degree photo to posts on June 9, 2016. If one has a compatible Samsung phone, Facebook will display a dedicated "view in VR" button, then users will have to insert the phone into their Gear VR headsets to watch the photo in a more immersive style.
    In July 2016, a $US 1 billion lawsuit was filed against the company alleging that it permitted the Hamas group to use it to perform assaults that ended the lives of 4 people. Facebook released the blueprints of Surround 360 camera on Github under Open-source license.

    Number of advertisers
    In February 2015, Facebook announced that it had reached two million active advertisers with most of the gain coming from small businesses. An active advertiser is an advertiser that has advertised on the Facebook platform in the last 28 days.[151] In March 2016, Facebook announced that it reached three million active advertisers with more than 70% from outside the US.

    Technical aspects
    The website's primary color is blue as Zuckerberg is red-green colorblind, a realization that occurred after a test undertaken around 2007; he explained in 2010: "blue is the richest color for me—I can see all of blue."[179][180] Facebook is built in PHP which is compiled with HipHop for PHP, a 'source code transformer' built by Facebook engineers that turns PHP into C++.[181] The deployment of HipHop reportedly reduced average CPU consumption on Facebook servers by 50%.
    Facebook is developed as one monolithic application. According to an interview in 2012 with Chuck Rossi, a build engineer at Facebook, Facebook compiles into a 1.5 GB binary blob which is then distributed to the servers using a custom BitTorrent-based release system. Rossi stated that it takes approximately 15 minutes to build and 15 minutes to release to the servers. The build and release process is zero downtime and new changes to Facebook are rolled out daily.[182]
    Facebook used a combination platform based on HBase to store data across distributed machines. Using a tailing architecture, new events are stored in log files, and the logs are tailed. The system rolls these events up and writes them into storage. The User Interface then pulls the data out and displays it to users. Facebook handles requests as AJAX behavior. These requests are written to a log file using Scribe (developed by Facebook).
    Data is read from these log files using Ptail, an internally built tool to aggregate data from multiple Scribe stores. It tails the log files and pulls data out (thus the name). Ptail data is separated out into three streams so they can eventually be sent to their own clusters in different data centers (Plugin impression, News feed impressions, Actions (plugin + news feed)). Puma is used to manage periods of high data flow (Input/Output or IO). Data is processed in batches to lessen the number of times needed to read and write under high demand periods (A hot article will generate a lot of impressions and news feed impressions which will cause huge data skews). Batches are taken every 1.5 seconds, limited by memory used when creating a hash table.
    After this, data is output in PHP format (compiled with HipHop for PHP). The backend is written in Java and Thrift is used as the messaging format so PHP programs can query Java services. Caching solutions are used to make the web pages display more quickly. The more and longer data is cached the less realtime it is. The data is then sent to MapReduce servers so it can be queried via Hive. This also serves as a backup plan as the data can be recovered from Hive. Raw logs are removed after a period of time.
    On March 20, 2014 Facebook announced a new open source programming language called Hack. Prior to public release, a large portion of Facebook was already running and "battle tested" using the new language.
    Facebook uses the Momentum platform from Message Systems to deliver the enormous volume of emails it sends to its users every day.

    History
    On July 20, 2008, Facebook introduced "Facebook Beta", a significant redesign of its user interface on selected networks. The Mini-Feed and Wall were consolidated, profiles were separated into tabbed sections, and an effort was made to create a "cleaner" look.[186] After initially giving users a choice to switch, Facebook began migrating all users to the new version starting in September 2008.[187] On December 11, 2008, it was announced that Facebook was testing a simpler signup process.

    Chat
    Facebook Chat was added April 6, 2008. It is a Comet-based[189] instant messaging application[190] which allows users to communicate with other Facebook users in a way similar in functionality to instant messaging software.
    Gifts

    Facebook launched Gifts on February 8, 2007, which allows users to send virtual gifts to their friends that appear on the recipient's profile. Gifts cost $1.00 each to purchase, and a personalized message can be attached to each gift.

    Marketplace

    On May 14, 2007, Facebook launched Marketplace, which lets users post free classified ads.[193] Marketplace has been compared to Craigslist by CNET, which points out that the major difference between the two is that listings posted by a user on Marketplace are seen only by users in the same network as that user, whereas listings posted on Craigslist can be seen by anyone.

    Messaging

    A new Messaging platform, codenamed "Project Titan", was launched on November 15, 2010. Described as a "Gmail killer" by some publications, the system allows users to directly communicate with each other via Facebook using several different methods (including a special email address, text messaging, or through the Facebook website or mobile app)—no matter what method is used to deliver a message, they are contained within single threads in a unified inbox. As with other Facebook features, users can adjust from whom they can receive messages—including just friends, friends of friends, or from anyone.[195][196] Email service was terminated in 2014 because of low uptake.[197] Aside from the Facebook website, messages can also be accessed through the site's mobile apps, or a dedicated Facebook Messenger app.

    Voice calls
    Since April 2011, Facebook users have had the ability to make live voice calls via Facebook Chat, allowing users to chat with others from all over the world. This feature, which is provided free through T-Mobile's new Bobsled service, lets the user add voice to the current Facebook Chat as well as leave voice messages on Facebook.

    Video calling

    On July 6, 2011, Facebook launched its video calling services using Skype as its technology partner. It allows one-to-one calling using a Skype Rest API.

    Video viewing

    In September 2014, Facebook announced that it delivers 1 billion video views per day and that it would begin showing everyone view counts on publicly posted videos from users, Pages, and public figures. It also confirmed that it is recommending additional videos to users after they have watched a video. Sixty-five percent of Facebook's video views are coming from mobile where Facebook's user base is shifting, and views grew 50 percent from May to July, in part thanks to the viral ALS Ice Bucket Challenge finding a home on Facebook.

    Tor hidden service

    facebookcorewwwi.onion
    In October 2014, Facebook announced[202] that users could now connect to the website through a Tor hidden service using the privacy-protecting Tor browser and encrypted using SSL.[203][204][205] Announcing the feature, Alec Muffett said "Facebook's onion address provides a way to access Facebook through Tor without losing the cryptographic protections provided by the Tor cloud. […] it provides end-to-end communication, from your browser directly into a Facebook datacentre."[203] Its URL address facebookcorewwwi.onion is a backronym, which stands for Facebook's Core WWW Infrastructure.
    User profile/personal timeline

    Facebook login/signup screen
    The format of individual user pages was revamped in late 2011 and became known as either a profile or personal timeline since that change.[206][207] Users can create profiles with photos and images, lists of personal interests, contact information, memorable life events, and other personal information, such as employment status.[208] Users can communicate with friends and other users through private or public messages, as well as a chat feature, and share content that includes website URLs, images, and video content.[209] A 2012 Pew Internet and American Life study identified that between 20 and 30 percent of Facebook users are "power users" who frequently link, poke, post and tag themselves and others.
    Old facebook verson.
    In 2007, Facebook launched Facebook Pages (also called "Fan Pages" by users) to allow "users to interact and affiliate with businesses and organizations in the same way they interact with other Facebook user profiles". On November 6, 2007, more than 100,000 Facebook pages were launched.[211]
    In July 2012, Facebook added a same-sex marriage icon to its timeline feature.[212] On February 14, 2014, Facebook expanded the options for user's gender setting, adding a custom input field that allows users to choose from a wide range of gender identities. Users can also set which set of gender-specific pronouns are used in reference to them throughout the site.[213][214] The change occurs after Nepal's first openly gay politician Sunil Babu Pant sent a letter to Zuckerberg in early 2012 to request the addition of an "Other" gender option for Facebook users; Facebook's official statement on the issue: "People can already opt out of showing their sex on their profile. We're constantly innovating on our products and features and we welcome input from everyone as we explore ways to improve the Facebook experience." On June 13, 2009, Facebook introduced a "Usernames" feature, whereby pages can be linked with simpler URLs such as

    https://www.facebook.com/name insted of https://www.facebook.com/profile.ph

    Many new smartphones offer access to Facebook services through either their Web browsers or applications. An official Facebook application is available for the operating systems Android, iOS, webOS, and Firefox OS. Nokia and Research In Motion both provide Facebook applications for their own mobile devices. As of January 2015, 745 million active users access Facebook through mobile devices every day. Sherr, Ian (January 28, 2015). "Facebook mobile users hit new highs, revenue jumps". Cnet. Retrieved March 2, 2015. In May 2014, Facebook introduced a feature to allow users to ask for information not disclosed by other users on their profiles. If a user does not provide key information, such as location, hometown, or relationship status, other users can use a new 'ask' button to send a message asking about that item to the user in a single click.
    News Feed . On September 6, 2006, News Feed was announced, which appears on every user's homepage and highlights information including profile changes, upcoming events, and birthdays of the user's friends.[218] This enabled spammers and other users to manipulate these features by creating illegitimate events or posting fake birthdays to attract attention to their profile or cause.[219] Initially, the News Feed caused dissatisfaction among Facebook users; some complained it was too cluttered and full of undesired information, others were concerned that it made it too easy for others to track individual activities (such as relationship status changes, events, and conversations with other users).
    According to the technology news web site Gizmodo on May 9, 2016, Facebook curators routinely suppresses or promotes news that is deemed to meet a political agenda. For example, articles about Black Lives Matter would be listed even if they did not meet the trending criteria of News Feed. Likewise positive news about conservative political figures were regularly excised from Facebook pages.

    Like button
    Main article: Facebook like button
    The like button is a social networking feature, allowing users to express their appreciation of content such as status updates, comments, photos, and advertisements. It is also a social plug-in of the Facebook Platform – launched on April 21, 2010[237][238] – that enables participating Internet websites to display a similar like button.The sheriff of Hampton, Virginia, US fired employees who liked the Facebook page of an adversary, and a federal appeals court in Virginia ruled that the US Constitution protects the rights of US citizens to like any Facebook page of their choosing. US Circuit Judge William Traxler likened the practice to displaying a "political sign in one's front yard."


    Accounts hacked in Bangalore, India
    In November 2011, several Facebook users in Bangalore, India reported that their accounts had been hacked and their profile pictures replaced with pornographic images. For more than a week, users' news feeds were spammed with pornographic, violent and sexual content, and it was reported that more than 200,000 accounts were affected. Facebook described the reports as inaccurate, and Bangalore police speculated that the stories may have been rumors spread by Facebook's competitors.

    "Free basics" controversy in India
    In February 2016, TRAI ruled against differential data pricing for limited services from mobile phone operators effectively ending zero-rating platforms in India. Zero rating provides access to limited number of websites for no charge to the end user. Net-neutrality supporters from India(SaveTheInternet.in) brought out the negative implications of Facebook Free Basic program and spread awareness to the public.[349] Facebook's Free Basics program[350] was a collaboration with Reliance Communications to launch Free Basics in India. The TRAI ruling against differential pricing marked the end of Free Basics in India.[351]
    Earlier, Facebook had spent $44 million USD in advertising and it implored all of its Indian users to send an email to the Telecom Regulatory Authority to support its program.[352] TRAI later asked Facebook to provide specific responses from the supporters of Free Basics.

    Safety Check bug
    On March 27, 2016, following a bombing in Lahore, Pakistan, Facebook activated its "Safety Check" feature, which allows people to let friends and loved ones know they are okay following a crisis or natural disaster, to people who were never in danger, or even close to the Pakistan explosion. Some users as far as the US, UK and Egypt received notifications asking if they were okay.[355][356]
    U.S. federal tax examination. On July 6, 2016, the U.S. Department of Justice filed a petition in the U.S. District Court in San Francisco, asking for a court order to enforce an administrative summons issued to Facebook, Inc., under Internal Revenue Code section 760 in connection with an Internal Revenue Service examination of Facebook's year 2010 U.S. Federal income tax return.[358][359]
    Support for terrorism lawsuit
    Further information: Criticism of Facebook § Incitement of terrorism
    In July 2016, a civil action for $1 billion in damages was filed in the United States District Court for the Southern District of New York on behalf of the victims and family members of four Israeli-Americans and one US citizen killed since June 2014 by Hamas terrorists who had used Facebook.The government of the United States has designated Hamas as a Foreign Terrorist Organization and the suit alleges that Facebook provided Hamas with "material support" in violation of US Anti-Terrorism laws.


    Impact

    Media impact

    In April 2011, Facebook launched a new portal for marketers and creative agencies to help them develop brand promotions on Facebook.[363] The company began its push by inviting a select group of British advertising leaders to meet Facebook's top executives at an "influencers' summit" in February 2010. Facebook has now been involved in campaigns for True Blood, American Idol, and Top Gear.[364] News and media outlets such as the Washington Post,[365] Financial Times[366] and ABC News[367] have used aggregated Facebook fan data to create various infographics and charts to accompany their articles. In 2012, the beauty pageant Miss Sri Lanka Online was run exclusively using Facebook.

    Social impact
    Main articles: Social networking service § Social impact, and Social impact of the Internet § Social networking and entertainment
    Facebook has affected the social life and activity of people in various ways. Facebook allows people using computers or mobile phones to continuously stay in touch with friends, relatives and other acquaintances wherever they are in the world, as long as there is access to the Internet. It has reunited lost family members and friends.[369][370] It allows users to trade ideas, stay informed with local or global developments, and unite people with common interests and/or beliefs through open, closed and private groups and other pages.

    Facebook's social impact has also changed how people communicate. Rather than having to reply to others through email, Facebook allows users to broadcast or share content to others, and thereby to engage others or be engaged with others' posts.
    Facebook has been successful and more socially impactful than many other social media sites. David Kirkpatrick, technology journalist and author of The Facebook Effect, believes that Facebook is structured in a way that is not easily replaceable. He challenges users to consider how difficult it would be to move all the relationships and photos to an alternative. Facebook has let people participate in an atmosphere with the "over the backyard fence quality" of a small town, despite the move to larger cities.[374] As per Pew Research Center survey, 44 percent of the overall population gets news through Facebook.

    United States
    Facebook's role in the American political process was demonstrated in January 2008, shortly before the New Hampshire primary, when Facebook teamed up with ABC and Saint Anselm College to allow users to give live feedback about the "back to back" January 5 Republican and Democratic debates.[391][392][393] Facebook users took part in debate groups organized around specific topics, register to vote, and message questions.
    Over a million people installed the Facebook application "US Politics on Facebook" in order to take part, and the application measured users' responses to specific comments made by the debating candidates.[395] This debate showed the broader community what many young students had already experienced: Facebook as a popular and powerful new way to interact and voice opinions. A poll by CBS News, UWIRE and The Chronicle of Higher Education claimed to illustrate how the "Facebook effect" has affected youth voting rates, support by youth of political candidates, and general involvement by the youth population in the 2008 election.
    The new social media, such as Facebook and Twitter, made use first of the personal computer and the Internet, and after 2010 of the smart phones to connect hundreds of millions of people, especially those under age 35. By 2008, politicians and interest groups were experimenting with systematic use of social media to spread their message among much larger audiences than they had previously reached.
    Facebook is having an impact on local government as well. Justin Smith, a Colorado sheriff uses Facebook to disseminate his ideas on matters relating to local, state, and national concerns. He also publicizes crimes, particularly those that his department solves. He has seven thousand followers on the social medium, considered a large number. Smith said that he rarely goes out in public "when I don't get feedback from folks. … Facebook is an interesting tool because I think it holds candidates and elected officials more accountable. Voters know where someone stands."
    As American political strategists turn their attention to the 2016 presidential contest, they identify Facebook as an increasingly important advertising tool. Recent technical innovations have made possible more advanced divisions and subdivisions of the electorate. Most important, Facebook can now deliver video ads to small, highly targeted subsets. Television, by contrast, shows the same commercials to all viewers, and so cannot be precisely tailored.

    Ban
    In many countries the social networking sites and mobile apps have been blocked temporarily or permanently. In Bangladesh, the government has been blocking Facebook, WhatsApp, Tango, Viber and many other sites and apps since November 18, 2015.

    In popular culture
    Facebook parade float in San Francisco Pride 2014
    American author Ben Mezrich published a book in July 2009 about Zuckerberg and the founding of Facebook, titled The Accidental Billionaires: The Founding of Facebook, A Tale of Sex, Money, Genius, and Betrayal.[402] The Social Network, a drama film directed by David Fincher and adapted from Mezrich's book, was released October 1, 2010.[403][unreliable source?] People portrayed in the movie, including Zuckerberg, have criticized its accuracy.[404] However a search of IMDB will reveal this to be a movie produced as standard entertainment.[405][unreliable source?] In response to the Everybody Draw Mohammed Day controversy and the banning of the website in Pakistan, an Islamic version of the website was created, called MillatFacebook.[406] "You Have 0 Friends", an April 2010 episode of the American animated comedy series, South Park, explicitly parodied Facebook.[407] At age 102, Ivy Bean of Bradford, England joined Facebook in 2008, making her one of the oldest people ever on Facebook.[408] At the time of her death in July 2010, she had 4,962 friends on Facebook and more than 56,000 followers on Twitter.[409] On May 16, 2011, an Israeli couple named their daughter after the Facebook "like" feature.[410][411] In July 2014, Shakira became the first celebrity to cross over 100 million likes, Cristiano Ronaldo is the second to reach 100 million likes, ahead of Rihanna and Eminem, who had 98 million and 89 million likes respectively.[412][413] Mark Zuckerberg posted a congratulatory message on the artist's wall

    Thaks for visit.......

    Oracle Java History

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    ORACLE JAVA

    Java is Programing Language.....
    Java is a general-purpose computer programming language that is concurrent, class-based, object-oriented , and specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere" (WORA), meaning that compiled Java code can run on all platforms that support Java without the need for recompilation.
    Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of computer architecture.
    As of 2016, Java is one of the most popular programming languages in use, particularly for client-server web applications, with a reported 9 million developers.

    Java was originally developed by James Gosling at Sun Microsystems (which has since been acquired by Oracle Corporation) and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++, but it has fewer low-level facilities than either of them.

    The original and reference implementation Java compilers, virtual machines, and class libraries were originally released by Sun under proprietary licences. As of May 2007, in compliance with the specifications of the Java Community Process, Sun relicensed most of its Java technologies under the GNU General Public License.
    Others have also developed alternative implementations of these Sun technologies, such as the GNU Compiler for Java (bytecode compiler), GNU Classpath (standard libraries), and IcedTea-Web (browser plugin for applets).

    The latest version is Java 8, which is the only version currently supported for free by Oracle, although earlier versions are supported both by Oracle and other companies on a commercial basis.


       History

    See also: Java (software platform)

    James Gosling, the creator of Java (2008)

    The TIOBE programming language popularity index graph from 2002 to 2015. Over the course of a decade Java (blue) and C (black) competing for the top position.
    James Gosling, Mike Sheridan, and Patrick Naughton initiated the Java language project in June 1991.
    Java was originally designed for interactive television, but it was too advanced for the digital cable television industry at the time.[23] The language was initially called Oak after an oak tree that stood outside Gosling's office. 
    Later the project went by the name Green and was finally renamed Java, from Java coffee. Gosling designed Java with a C/C++-style syntax that system and application programmers would find familiar.
    Oracle name is based on this tree..
    Sun Microsystems released the first public implementation as Java 1.0 in 1995.[26] It promised "Write Once, Run Anywhere" (WORA), providing no-cost run-times on popular platforms. 
    Fairly secure and featuring configurable security, it allowed network- and file-access restrictions. 
    Major web browsers soon incorporated the ability to run Java applets within web pages, and Java quickly became popular, while mostly outside of browsers, that wasn't the original plan.
    In January 2016, Oracle announced that Java runtime environments based on JDK 9 will discontinue the browser plugin.
    The Java 1.0 compiler was re-written in Java by Arthur van Hoff to comply strictly with the Java 1.0 language specification. With the advent of Java 2 (released initially as J2SE 1.2 in December 1998 – 1999), new versions had multiple configurations built for different types of platforms. 
    J2EE included technologies and APIs for enterprise applications typically run in server environments, while J2ME featured APIs optimized for mobile applications. The desktop version was renamed J2SE.
    In 2006, for marketing purposes, Sun renamed new J2 versions as Java EE, Java ME, and Java SE, respectively.

    In 1997, Sun Microsystems approached the ISO/IEC JTC 1 standards body and later the Ecma International to formalize Java, but it soon withdrew from the process. Java remains a de facto standard, controlled through the Java Community Process. 
    At one time, Sun made most of its Java implementations available without charge, despite their proprietary software status. 
    Sun generated revenue from Java through the selling of licenses for specialized products such as the Java Enterprise System.

    On November 13, 2006, Sun released much of its Java virtual machine (JVM) as free and open-source software, (FOSS), under the terms of the GNU General Public License (GPL). 
    On May 8, 2007, Sun finished the process, making all of its JVM's core code available under free software/open-source distribution terms, aside from a small portion of code to which Sun did not hold the copyright.

    Sun's vice-president Rich Green said that Sun's ideal role with regard to Java was as an "evangelist". 
    Following Oracle Corporation's acquisition of Sun Microsystems in 2009–10, Oracle has described itself as the "steward of Java technology with a relentless commitment to fostering a community of participation and transparency". 
    This did not prevent Oracle from filing a lawsuit against Google shortly after that for using Java inside the Android SDK (see Google section below). 
    Java software runs on everything from laptops to data centers, game consoles to scientific supercomputers.
    On April 2, 2010, James Gosling resigned from Oracle



    Versions

    Java version history
    As of 2015, only Java 8 is supported ("publicly"). Major release versions of Java, along with their release dates:



    JDK 1.0 (January 21, 1996)
    JDK 1.1 (February 19, 1997)
    J2SE 1.2 (December 8, 1998)
    J2SE 1.3 (May 8, 2000)
    J2SE 1.4 (February 6, 2002)
    J2SE 5.0 (September 30, 2004)
    Java SE 6 (December 11, 2006)
    Java SE 7 (July 28, 2011)
    Java SE 8 (March 18, 2014)

    Principles

    There were five primary goals in the creation of the Java language:[16]
    1) It must be "simple, object-oriented, and familiar".
    2) It must be "robust and secure".
    3) It must be "architecture-neutral and portable".
    4) It must execute with "high performance".
    5) It must be "interpreted, threaded, and dynamic".


    Performance

    Main article: Java performance
    Programs written in Java have a reputation for being slower and requiring more memory than those written in C++.
    However, Java programs' execution speed improved significantly with the introduction of just-in-time compilation in 1997/1998 for Java 1.1, the addition of language features supporting better code analysis (such as inner classes, the StringBuilder class, optional assertions, etc.), and optimizations in the Java virtual machine, such as HotSpot becoming the default for Sun's JVM in 2000.
    With Java 1.5, the performance was improved with the addition of the java.util.concurrent package, including Lock free implementations of the ConcurrentMaps and other multi-core collections, and it was improved further Java 1.6.
    Some platforms offer direct hardware support for Java; there are microcontrollers that can run Java in hardware instead of a software Java virtual machine, and ARM based processors can have hardware support for executing Java bytecode through their Jazelle option (while its support is mostly dropped in current implementations of ARM).


    Java platform

    Main articles: Java (software platform) and Java virtual machine
    Java Control Panel, version 7 , One design goal of Java is portability, which means that programs written for the Java platform must run similarly on any combination of hardware and operating system with adequate runtime support.
    This is achieved by compiling the Java language code to an intermediate representation called Java bytecode, instead of directly to architecture-specific machine code. Java bytecode instructions are analogous to machine code, but they are intended to be executed by a virtual machine (VM) written specifically for the host hardware. End users commonly use a Java Runtime Environment (JRE) installed on their own machine for standalone Java applications, or in a web browser for Java applets.
    Standard libraries provide a generic way to access host-specific features such as graphics, threading, and networking. The use of universal bytecode makes porting simple. However, the overhead of interpreting bytecode into machine instructions makes interpreted programs almost always run more slowly than native executables. However, just-in-time (JIT) compilers that compile bytecodes to machine code during runtime were introduced from an early stage. 
    Java itself is platform-independent, and is adapted to the particular platform it is to run on by a Java virtual machine for it, which translates the Java bytecode into the platform's machine language.


    Implementations

    See also: Free Java implementations
    Oracle Corporation is the current owner of the official implementation of the Java SE platform, following their acquisition of Sun Microsystems on January 27, 2010. This implementation is based on the original implementation of Java by Sun. The Oracle implementation is available for Microsoft Windows (still works for XP, while only later versions currently "publicly" supported), Mac OS X, Linux and Solaris. Because Java lacks any formal standardization recognized by Ecma International, ISO/IEC, ANSI, or other third-party standards organization, the Oracle implementation is the de facto standard.

    The Oracle implementation is packaged into two different distributions: The Java Runtime Environment (JRE) which contains the parts of the Java SE platform required to run Java programs and is intended for end users, and the Java Development Kit (JDK), which is intended for software developers and includes development tools such as the Java compiler, Javadoc, Jar, and a debugger.
    OpenJDK is another notable Java SE implementation that is licensed under the GNU GPL. The implementation started when Sun began releasing the Java source code under the GPL. As of Java SE 7, OpenJDK is the official Java reference implementation.

    The goal of Java is to make all implementations of Java compatible. Historically, Sun's trademark license for usage of the Java brand insists that all implementations be "compatible". This resulted in a legal dispute with Microsoft after Sun claimed that the Microsoft implementation did not support RMI or JNI and had added platform-specific features of their own. Sun sued in 1997, and in 2001 won a settlement of US$20 million, as well as a court order enforcing the terms of the license from Sun.[39] As a result, Microsoft no longer ships Java with Windows.


    Java Platform independent

    Java is essential to Java EE, and an even more rigorous validation is required to certify an implementation. This environment enables portable server-side applications.

    java is independent


    Automatic memory management

    Java uses an automatic garbage collector to manage memory in the object lifecycle. The programmer determines when objects are created, and the Java runtime is responsible for recovering the memory once objects are no longer in use. Once no references to an object remain, the unreachable memory becomes eligible to be freed automatically by the garbage collector. Something similar to a memory leak may still occur if a programmer's code holds a reference to an object that is no longer needed, typically when objects that are no longer needed are stored in containers that are still in use. If methods for a nonexistent object are called, a "null pointer exception" is thrown.
    As in C++ and some other object-oriented languages, variables of Java's primitive data types are either stored directly in fields (for objects) or on the stack (for methods) rather than on the heap, as is commonly true for non-primitive data types (but see escape analysis). This was a conscious decision by Java's designers for performance reasons.
    Java contains multiple types of garbage collectors. By default,[citation needed] HotSpot uses the parallel scavenge garbage collector. However, there are also several other garbage collectors that can be used to manage the heap. For 90% of applications in Java, the Concurrent Mark-Sweep (CMS) garbage collector is sufficient. Oracle aims to replace CMS with the Garbage-First collector (G1).


    Syntax

    Java syntax
    The syntax of Java is largely influenced by C++. Unlike C++, which combines the syntax for structured, generic, and object-oriented programming, Java was built almost exclusively as an object-oriented language.[16] All code is written inside classes, and every data item is an object, with the exception of the primitive data types, i.e. integers, floating-point numbers, boolean values, and characters, which are not objects for performance reasons. Java reuses some popular aspects of C++ (such as printf() method).

    Unlike C++, Java does not support operator overloading[47] or multiple inheritance for classes, though multiple inheritance is supported for interfaces.[48] This simplifies the language and aids in preventing potential errors and anti-pattern design.[citation needed]
    Java uses comments similar to those of C++. There are three different styles of comments: a single line style marked with two slashes (//), a multiple line style opened with /* and closed with */, and the Javadoc commenting style opened with /** and closed with */. The Javadoc style of commenting allows the user to run the Javadoc executable to create documentation for the program.

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