Java Tutorial

Q. What is Java?

Ans. Java is a Machine Independent (Run on any computer) and High Level Programming Language. It is developed by Sun Microsoft's in 1995. It runs on basically Mac OS, Windows XP/7/8.1/10 and various versions of UNIX. Java doesn’t use header file instead use packages.

In Java every class should always a part of package. If the user does not build any package then the compiler will automatically make default package i.e nothing

Platform:- Any software and hardware in which a program runs is known as plat form. Since Java has its own run time environment JRE and API, It is called Platform.

Where is used java ?

According to Sun Micro System 4 million devices run java. there are many devices currently runs in java i.e.

1) Desktop Application such as Media Player, Adobe reader.

2) Mobile Application

3) Web Applications

4) Games etc.

Features of Java: -

The most important feature of the java is the platform  independent  language.                                                                                                                                                                                                                     Platform Independent means that we write and compile the source code in one machine or platform and execute or run on any operating system i.e Windows, Linux, Mac etc

1) Simple:- Java is easy to learn and its syntax is quite simple and easy to understand.

2) Object Oriented: - In Java everything is object which has some data and behavior.
3) Platform Independent:- Unlike another programming languages such as C, C++ etc which are compiled into platform specific machines. Java is write-once, run anywhere languages.
On compilation Java program is compiled in bytecode. This byte code is platform independent and can be run on any machine. and this byte code format also provide security.

4) Multi thread: - Java multithreading feature allow the user can do many task

simultaneously.

5)  Secure: - Java program is always run on java  Runtime environment. Java is virus free, temper free system hence it is more secured.

6) Robust: - Java checks the compile time errors and run time errors.

7) Interpreted: - It is used to run Java Programs. The programs are compiled by JVM Code called byte code. The byte code is Machine independent and is able to run on any machine (computer)

8) High Performance:- Java is an interpreted language, so it will never be asfast as compiled language like C, C++. But Java enables high performance with the use of just-in-time compiler.

Application of Java:-

1) Standalone application: -

It is also known as desktop application or window based applications e.g. Window media player, Antivirus etc. Awt and Swing are used in java for creating Standalone applications

2) Mobile application: -

Those applications that is created for mobile devices i.e. Android and Java

3) Web application: -

An application that runs on the server side and creates dynamic pages is called web applications currently, servlet, jsp etc Technologies are used for creating web applications

4) Enterprise Application: -

Enterprise applications are used for making Banking applications. It has the advantage of high level security. EJB is used for creating enterprise application.     
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