So, you want to program in Java? That's great, and you've come to the right place. The MY IT WORLD provides a self-guided introduction to Java programming, starting with the basics and covering all the core concepts you need to know to become a productive Java developer. This series is technical, with plenty of code examples to help you grasp the concepts as we go along. I will assume that you already have some programming experience, just not in Java.
What is Java?
You can think of Java as a general-purpose, object-oriented language that looks a lot like C and C++, but which is easier to use and lets you create more robust programs.
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. This tutorial gives a complete understanding of Java.
This reference will take you through simple and practical approach while learning Java Programming language.
Audience
This reference has been prepared for the beginners to help them understand the basic to advanced concepts related to Java Programming language.
Prerequisites
Before you start doing practice with various types of examples given in this reference, I'm making an assumption that you are already aware about what is a computer program and what is a computer programming language?
Three editions of Java
Sun Microsystems released the Java 1.0 software development kit (JDK) in 1995. The first JDK was used to develop desktop applications and applets, and Java subsequently evolved to encompass enterprise-server and mobile-device programming. Storing all of the necessary libraries in a single JDK would have made the JDK too large to distribute, especially because distribution in the 1990s was limited by small-size CDs and slow network speeds. Since most developers didn't need every last API (a desktop application developer would hardly need to access enterprise Java APIs), Sun solved the distribution issue by factoring Java into three main editions. These eventually became known as Java SE, Java EE, and Java ME:
- Java Platform, Standard Edition (Java SE) is the Java platform for developing client-side applications, which run on desktops, and applets, which run in web browsers.
- Java Platform, Enterprise Edition (Java EE) is the Java platform built on top of Java SE, which is used exclusively to develop enterprise-oriented server applications. Server-side applications include servlets, which are Java programs that are similar to applets but run on a server rather than a client. Servlets conform to the Java EE Servlet API.
- Java Platform, Micro Edition (Java ME) is also built on top of Java SE. It is the Java platform for developing MIDlets, which are Java programs that run on mobile information devices, and Xlets, which are Java programs that run on embedded devices.
Java is:
Object Oriented: In Java, everything is an Object. Java can be easily extended since it is based on the Object model.
Platform independent: 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. This byte code is distributed over the web and interpreted by virtual Machine (JVM) on whichever platform it is being run.
Simple: Java is designed to be easy to learn. If you understand the basic concept of OOP Java would be easy to master.
Secure: With Java's secure feature it enables to develop virus-free, tamper-free systems. 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.
Portable: Being architectural-neutral and having no implementation dependent aspects of the specification makes Java portable. Compiler in Java is written in ANSI C with a clean portability boundary which is a POSIX subset.
Robust: Java makes an effort to eliminate error prone situations by emphasizing mainly on compile time error checking and runtime checking.
Multithreaded: 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 light weight process.
High Performance: With the use of Just-In-Time compilers, Java enables high performance.
Distributed: Java is designed for the distributed environment of the internet.
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.
Prerequisite:
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 xp/7/8 operating system.
Java JDK 8
Microsoft Notepad or any other text editor
