JAVA Introduction

History of Java

Java is a general-purpose, concurrent, class-based, object-oriented computer programming language that is specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another. 

James Gosling initiated the Java language project in June 1991 that time it was called “Oak “. Later in 1995 first version of java (Java1.0) was released by Sun Microsystems.

In January 1995, Oak was renamed Java (as the name Oak was already in use), and developed into a robust programming language for building WWW-based applications. As a proof-of-concept, they developed a web browser known as Hot Java (written in Java) that is capable of running mini Java applications (known as Applets) that are embedded in WWW pages. This feature of Hot Java was then taken up by Netscape and Microsoft. Later in 1995 Sun released the initial Java Development Kit (JDK) and Hot Java.

What is Java?

Java is a programming language which is now a subsidiary of Oracle Corporation originally developed by James Gosling at Sun Microsystems in 1995.

Java technology's versatility, efficiency, platform portability, and security make it the ideal technology for network computing.

Today Java is used in all fields including enterprise applications; Data Enters, game consoles to scientific supercomputers, cell phones, Internet, fiancé sector, telecom domain etc.

Java is an object oriented programming language .Java is third generation programming language .

Java is Simple, Object-Oriented, Distributed, Interpreted, Robust, Secure, Architecture-Neutral, Portable, High-Performance, Multithreaded  and Dynamic programming  language.

Where and why Java is used?

Java is used where we need versatility, efficiency, platform portability, and security.

Today Java is used in all fields including enterprise applications; data enters, game consoles to scientific supercomputers, cell phones, Internet, financé sector, telecom domain etc.

Java is an object oriented programming language. Java is third generation programming language .So Java is used as Simple, Object-Oriented, Distributed, Interpreted, Robust, Secure, Architecture-Neutral, Portable, High-Performance, Multithreaded and Dynamic programming  language.

Principles

There were five primary goals in the creation of the Java language

1.     It should be "simple, object-oriented and familiar"

2.     It should be "robust and secure"

3.     It should be "architecture-neutral and portable"

4.     It should execute with "high performance"

5.     It should be "interpreted, threaded, and dynamic"

Versions

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)

Editions

• Java Card for smartcards.
• Java Platform, Micro Edition (Java ME) — targeting environments with limited resources.
• Java Platform, Standard Edition (Java SE) — targeting workstation environments.
• Java Platform, Enterprise Edition (Java EE) — targeting large distributed enterprise or Internet environments.

Advantages of Java

JAVA is an open source code object oriented programming (OOP) language by  Sun Microsystems that together provide a system for developing an application software and deploying it in a cross-platform environment(platform independent ).

 Java is used in computing platforms from embedded devices and mobile phones, enterprise servers and supercomputers .Java is also used into nearly everywhere in mobile phones, Web servers and enterprise applications, and desktop computers, Applets are often used on World Wide Web.

Advantages of JAVA:

1. Java is an open source

2. Platform independent

3. Java API's can easily be accessed by developers

4. Java performs supports garbage collection, so doesn't need extra focus on memory management as java support automatic memory managements.

5. Java supports exception handling.

6. Java always allocates objects on the stack

7. Multi-platform support language and support for web-services

8. Using JAVA we can develop dynamic web applications

9. It allows you to create modular programs and reusable codes

10. Java is simple: Java is simple. It doesn't need prier knowledge of C,C++ etc .You can starts from only. Java is design to be easy to use. Java is easy to write, compile, debug, and learn thanother programming languages. Java uses automatic memory allocation and garbage collection where else C++ requires the programmer to allocate memory and to collect garbage so these languages are more complex.

11.Java is object-oriented: Java is cantered on creating objects, manipulating objects, and making objects work together. This allows us to create an application in modular programs and reusable code.

12.Java is platform-independent: Java allow us make an application and run anywhere. As when an application complies then Java converts into Byte code. This byte code can be run anywhere (Mean any hardware Supported or OS).

13.Java is distributed: Using Java we can work on distributed computers involves several computers on a network working together. Java is designed to make distributed computing easy with the networking capability that is inherently integrated into it. We can write a network programs in Java are which will send and receive data to and from a file.

14.Java is robust: Java is a robust means reliable and no programming language can really assure reliability. Java puts a lot of emphasis on early checking for possible errors. Java compilers are able to detect many problems that would first show up during execution time in other languages.

15.Java is multithreaded: Java supports multithreading are the capability for a program to perform several tasks simultaneously within a program.

16.Java is interpreted programming Languages: The programs are compiled into Java Virtual Machine code called bytecode using interpreter.The bytecode is machine independent and is able to run on any machine that has a Java interpreter. With Java, the program need only be compiled once, and the byte code generated by the Java compiler can run on any platform.

17.Java is secure:  Java is a first programming language to consider security as part of its design. The Java language, compiler, interpreter, and runtime environment were each developed with security in mind.

Disadvantages of Java 

• Performance Slower Than C or C++: Java can be perceived as significantly slower and more memory-consuming than natively compiled languages such as C or C++.
• Java applications runs on JVM which is a program .It may be written incorrect .
• Java applications runs on JVM which cause slow down to programs as compare to C and C++

Limitations of Java Language

 Of course each languages has some limitations and so java have some limitations:

• The look & feel of the GUI written in Java using Swing may not be the same as the widget look and feel of the underlying operating system.
• Java largely supports IEEE-754 floating point arithmetic, but certain features are not supported even with the use of the ‘strictfp’ modifier in Java.
• ·While bytecodes make Java a portable language to a great extent, they cause the performance to slow down to a certain extent as well.
• Java uses the automatic garbage collector to handle all the memory management and the programmer has no control on it.
• Different JVM for different platform

Future of Java Language

Java 2 Platform, Standard Edition 5.0, code- named "Tiger".

TheJava platform has split into three branches (Standard, Enterprise, and Micro) and the JDK has been released to the open source community. The Java language has expanded to include annotations, generics, enumerations, advanced collections, and more. It has also begun to share its home, the JRE, with dynamic languages like Groovy, JRuby, and Rhino, to name a few. In fact, if you think about it, especially over the last few years, we've collectively watched as the moniker of Java has transformed from a language into a veritable platform.

HTML Basic Terms

HTML

Stands for Hyper Text Markup Language. HTML is a markup language that is the core language of the world wide web. HTML defines the structure of a web document as well as the layout of text and various elements on it such as buttons and images.

HTML Document

A document that is written in HTML. HTML document is synonomous with HTML page.

HTML Editor

A software tool used for editing the content of webpages. HTML editors present the page being edited exactly the way it will be displayed in a web browser.

HTML Form

A form on a webpage filled out by the user that sends data to the web server.

HTML Page

A document that is written in HTML. HTML page is synonomous with HTML document.

HTML Tags

Pieces of code that are used to identify and structure different parts of an HTML document. Because of HTML tags, a web browser knows how to display an HTML document.

HTTP

Stands for Hyper Text Transfer Protocol. HTTP is a protocol that typically runs on port 80 and is used to send web resources such as images and HTML documents across the world wide web. Through the use of HTTP, data is sent from an HTTP server program ( a web server ) to an HTTP client program ( a web browser ).

HTTP Client

A software tool that receives data from a web server through the HTTP protocol. Some HTTP clients include web browsers like Mozilla Firefox and Netscape.

HTTP Server

A software tool used to store and send data over the world wide web to HTTP clients. Some HTTP servers include Apache and IIS.

HTTPS

Stands for Hyper Text Transfer Protocol Secure. HTTPS is a secure version of HTTP and provides communication using SSL. With HTTPS, data that is sent between a web server and a web client is encrypted.

Hyperlink

A link on a webpage to another web document, usually a webpage, but can also be an image, a sound, or any other web resource. Hyperlink is synonomous with Link and Hotlink.

Hypermedia

An extension to hypertext which includes graphics, audio, and video.

Hypertext

Text that is linked to other documents in a way that makes it pssobile for readers to read related documents by clicking on a highlighted word or symbol.