GENERAL INFORMATION OF JAVA


Java Tutorial

Java is a high-level programming language originally developed by Sun Microsystems and released in 1995. Java runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX.


Java Overview

Java programming language was originally developed by Sun Microsystems which was initiated by James Gosling and released in 1995 as core component of Sun Microsystems’ Java platform (Java 1.0 [J2SE]). As of December 2008, the latest release of the Java Standard Edition is 6 (J2SE). With the advancement of Java and its widespread popularity, multiple configurations were built to suite various types of platforms. Eg: J2EE for Enterprise Applications, J2ME for Mobile Applications.
Sun Microsystems has renamed the new J2 versions as Java SE, Java EE and Java ME, respectively. Java is guaranteed to be Write Once, Run Anywhere.
Java is:
    Object Oriented : In Java, everything is an Object. Java can be easily extended since it is based on the Object model. Object is based on real time entity.

    Platform Independent :Java is platform-independent because it is compiled to a bytecode that can be run on any device that has a Java Virtual Machine (JVM). Unlike many other programming languages including C and C++, when Java is compiled, it is not compiled into platform specific machine, rather into platform independent byte code.

    Simple :Java is designed to be easy to learn. If you understand the basic concept of OOPS,Java would be easy to use.

    Secure : With Java's secure feature, it enables to develop virus-free. Authentication techniques are based on public-key encryption.

    Architectural-neutral :Java compiler generates an architecture-neutral object file format, which makes the compiled code to be executable on many processors, with the presence of Java runtime system.

    Multithreading : With Java's multithreaded feature, it is possible to write programs that can do many tasks simultaneously. This design feature allows developers to construct smoothly running interactive applications.

    Interpreted :Java byte code is translated on the fly to native machine instructions and is not stored anywhere. The development process is more rapid and analytical since the linking is an incremental and lightweight process.

    High Performance: With the use of Just-In-Time compilers, Java enables high performance.

    Dynamic: Java is considered to be more dynamic than C or C++ since it is designed to adapt to an evolving environment. Java programs can carry extensive amount of run-time information that can be used to verify and resolve accesses to objects on run-time.

History of Java:

James Gosling initiated the Java language project in June 1991 for use in one of his many set-top box projects. The language, initially called Oak after an oak tree that stood outside Gosling's office, also went by the name Green and ended up later being renamed as Java, from a list of random words.
Sun 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.
On 13 November 2006, Sun released much of Java as free and open source software under the terms of the GNU General Public License (GPL).
On 8 May 2007, Sun finished the process, making all of Java's core code free and open-source, aside from a small portion of code to which Sun did not hold the copyright.


Tools you will need:

For performing the examples discussed in this tutorial, you will need a Pentium 200-MHz computer with a minimum of 64 MB of RAM (128 MB of RAM recommended).You also will need the following softwares:
  • Linux 7.1 or Windows operating system.
  • Java JDK 8
  • Microsoft Notepad or any other text editor


    • Java Environment Setup

    Before we proceed further, it is important that we set up the Java environment correctly. This section guides you on how to download and set up Java on your machine.
    Please follow the following steps to set up the environment. Java SE is freely available from the linkDownload Java
    So you download a version based on your operating system.Follow the instructions to download Java and run the .exe to install Java on your machine. Once you installed Java on your machine, you would need to set environment variables to point to correct installation directories:

    Setting up the path for windows:
    Assuming you have installed Java in c:\Program Files\java\jdk directory:
  • Right-click on 'My Computer' and select 'Properties'.
  • Click on the 'Environment variables' button under the 'Advanced' tab.
  • Now, alter the 'Path' variable so that it also contains the path to the Java executable. Path='%Path%;c:\Program Files\java\jdk1.8.0_341\bin'.


    • Popular Java Editors:

    To write your Java programs, you will need a text editor. There are even more sophisticated IDEs available in the market. But for now, you can consider one of the following:
  • Eclipse: Is also a Java IDE developed by the eclipse open-source community and can be downloaded from http://www.eclipse.org/
  • Textpad: On Windows machine, you can use any simple text editor (Recommended for this), and can be downloaded from https://www.textpad.com/download (TextPad).
  • Netbeans:Is a Java IDE that is open-source and free which can be downloaded from http://www.netbeans.org/index.html


    • (Core Java - Java Basics)