Java ???

What is Java? Where do we need Java? Why only Java? Javascript and Java, are they similar? These are the few questions which will strike to your mind when you hear this word. Well, if you are familiar with this programming language then you have a clear understanding about it.

            Java was invented by James Gosling, Patrick Naughton, Chris Warth, Ed Frank and Mike Sheridan at Sun Microsystems, Inc. in 1991. It was initially called ‘Oak’ but was renamed to ‘Java’ in 1995. 

Java is an object oriented high level programming language. Object oriented because, it gives priority to data on which it is implemented rather than the code. It is a high level language because, codes are written in human understandable language. Java is similar to ‘C++’ but it is completely different from it. Java derives many of its syntaxes and programming styles from C++, but the purpose and working environment is different. Java is used almost everywhere in the computing world. 

Java is available in different forms:
JSP (Java Server Page): Like PHP and ASP, JSPs based on a code with normal HTML tags, which helps in creating dynamic web pages. 
Java Applets : This is another type of Java program used within a web page to add many new features to a web browser.
J2EE : The software Java 2 Enterprise Edition are used by various companies to transfer data based on XML structured documents between one another.
JavaBeans : This is something like Visual Basic and a reusable software component that can be easily assemble to create some new and advanced application.
Mobile Java : Besides the above technology, Java is also used for various entertainment devices especially mobile phone.

            Now, why do we need only Java for all? What about other programming languages? Answer is simple. Java is platform independent. The code written in java is compiled to give an output in the form of ‘Bytecode’. It is not an executable code. Bytecode is highly optimized set of instructions designed to be executed by the Java run-time system, which is called as Java Virtual Machine (JVM). It requires target machines to have JVM installed in it. So it possible to run same bytecode in any of the target machines with JVM, which will interpret the code for execution. The security is achieved in a very general manner. The code is allowed to execute in a confined boundary under the run time environment of java. It cannot have any unauthorized access outside this environment. Thus it cannot harm the systems. 

            Then, what is this javascript? Javascript is a scripting language for client side web documents. To increase the functionality of HTML codes, javascript is designed. There is no connection between java and javascript. Javascript is named so because; during the time of invention of javscript, Java was a very famous and powerful. The idea was to make ‘js’ popular, hence java was made a part of its name and named as ‘Javascript’. So it can be said that Java is a powerful, flexible, efficient, user friendly and robust language with a huge collection of built in libraries.

Further reference: The Complete Reference Java by Herbert Schildt