What is Java language? Basics
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 relicensedmost 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
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. 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.
Sun Microsystems released the first public implementation as Java 1.0 in 1995. 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.
What is the Web server?
Web technologies are the establishments that make it possible for computers to communicate and share resources. And the Web is a collection of document, image, video, and sound files that can be linked and accessed over the Internet using a protocol called HTTP. It is also called as World Wide Web. It was discovered by computer scientist sir Tim Berners-Lee in 1989. Web is global information medium which users can read and write via computers connected to the computers. Web was specifications for URLs, HTML, and HTTP.
|
|
|
A Web site is a related collection of World Wide Web (WWW) files that includes a beginning file called a home page. Each Web site contains a home page, which is the first document users see when they enter the site. The site might also contain additional documents and files.
Every Website sites on a computer known as a Web server. This server is always connected to the internet. "Web server" can refer to hardware or software, or both of them working together. A web server is a computer that stores websites on the Internet and delivers web pages to viewers upon request. Every web server has a unique address, called an Internet Protocol address, that tells other computers connected to the Internet where to find the server.
There comes a word like web page. A web page is accessed by entering a URL address and may contain text, graphics, and hyperlinks to other web pages and files.All web pages that you see on the Internet use HTML to format its pages for display in a web browser.
Web servers are used to store process and deliver the pages of a web site to users.So a Web Server is basically a PC that is designed to accept requests from remote computers and send on the information requested.
What is CSS? Features of CSS
CSS is the short form of Cascading which is a style sheet language used to describe the presentation of a document written in a markup language. In another word, CSS are used to describe the appearance of Web content.
Cascading Style Sheets - a language for describing the appearance of HTML-documents. Simply put, CSS language is designed to give the required appearance of HTML-documents. The purpose of CSS was to separate the description of the logical structure of the web page from her appearance. By using CSS web developer may specify the pages to separate its components and different typefaces and font sizes, colors elements padding elements from each other, arrangement of the individual blocks on the page, etc. Current version – CSS 3.
|
|
|
CSS basically provides style information to web documents.With CSS you can determine the position of the elements, color, font, margins, borders, lines, height, width, background images and much more. CSS is used to control presentation, formatting, and layout. Whereas HTML was the basic structure of your website, CSS is what gives your entire website its style.
CSS was a revolution in the world of web-design. Specific Benefits of CSS:
Control layout of many documents from one single style sheet;
Features of Cascading Style Sheets.
- The ability to manage any number of design documents from one single style sheet;
- The quality design of pages, which is supported by all browsers.
- Different views for different media (screen, print, etc...);
- CSS allows you to save time - you can, once creating CSS styles, use it with a variety of web pages
-Pages load faster - if you use CSS, you do not need to repeat the style of HTML
- More opportunities - in the CSS style attributes much more than with HTML
Дата добавления: 2018-06-01; просмотров: 553; Мы поможем в написании вашей работы! |
Мы поможем в написании ваших работ!