You use word processors to write documents, Web browsers to explore the Internet, and email programs to send email. These are all examples of software that runs on computers. If you take a computer right from the factory and give no instructions to this computer, the computer can’t do word processing, the computer can’t surf the Web, and it can’t do anything. All a computer can do is follow the instructions that people give to it. The group of instructions is a program. A group of program or code is known as Software. Software is developed using programming languages.
There are many programming languages that can be used for developing programs but why Java?
The answer is that Java enables users to develop and deploy applications on the Internet for servers, desktop computers, and small hand-held devices. The future of computing is being profoundly influenced by the Internet, and Java promises to remain a big part of that future. Java is the Internet programming language and one of the most powerful programming languages.
Java has become enormously popular. Its rapid rise and wide acceptance can be traced to its design characteristics, particularly its promise that you can write a program once and run it anywhere. As stated by Sun, Java is simple, object oriented, distributed, interpreted, robust, secure, architecture neutral, portable, high performance, multithreaded, and dynamic.
Java is a full-featured, general-purpose programming language that can be used to develop robust mission-critical applications. Today, it is employed not only for Web programming, but also for developing standalone applications across platforms on servers, desktops, and mobile devices. It was used to develop the code to communicate with and control the robotic rover on Mars. Many companies that once considered Java to be more hype than substance are now using it to create distributed applications accessed by customers and partners across the Internet. For every new project being developed today, companies are asking how they can use Java to make their work easier.
Java is a mature programming language that is easy to learn. At the same time it is also a vast collection of technologies that are so diverse that beginners often don’t know where to start.
With the development of Java, applications have never been easier or faster. The aim of the Java is to provide developers with a powerful set of APIs while shortening development time, reducing application complexity, and improving application performance.
Java is not only an object-oriented programming language; it is also a set of technologies that make software development more rapid and resulting applications more robust and secure. For years Java has been the technology of choice because of the benefits it offers:
- platform independence
- ease of use
- complete libraries that speed up application
- extensive industry support
Sun Microsystems introduced Java in 1995 which was developed by team led by James Gosling and Java (which was known as Oak) – were used in embedded chips in consumer electronic appliances. In 1995, it was renamed as Java, and it was redesigned for developing Internet appliances. The growth of the Internet had much to contribute to the early success of Java.
Having said that, applets were not the only factor that made Java shine. The other most appealing feature of Java was its platform-independence promise, hence the slogan “Write Once, Run Anywhere.” What this means is the very same program you write will run on Windows, Unix, Mac, Linux, and other operating systems. This was something no other programming language could do. At that time, C and C++ were the two most commonly used languages for developing serious applications. Java seemed to have stolen their thunder since its first birthday.
That was Java version 1.0.
In 1997, Java 1.1 was released, adding significant features such as a better event model, Java Beans, and internationalization to the original.
Java 1.2 was launched in December 1998. Three days after it was released, the version number was changed to 2, marking the beginning of a huge marketing campaign that started in 1999 to sell Java as the “next generation” technology. Java 2 was sold in four flavors: the Standard Edition (J2SE), the Enterprise Edition (J2EE), the Micro Edition (J2ME), and Java Card (that never adopted “2” in its brand name).
The next version released in 2000 was 1.3, hence J2SE 1.3. 1.4 came two years later to make J2SE 1.4. J2SE version 1.5 was released in 2004. However, the name Java 2 version 1.5 was then changed to Java 5.
On November 13, 2006, a month before the official release date of Java 6, Sun Microsystems announced that it had open-sourced Java. Java SE 6 was the first Java release for which Sun Microsystems had invited outside developers to contribute code and help fix bugs. True that the company had in the past accepted contributions from non-employees, like the work of Doug Lea on multithreading, but this was the first time Sun had posted an open invitation. The company admitted that they had limited resources, and outside contributors would help them cross the finish line sooner.
In May 2007 Sun released its Java source code to the OpenJDK community as free software. IBM, Oracle and Apple later joined OpenJDK.
In 2010 Oracle acquired Sun.
Java 7, code-named Dolphin, was released in July 2011 and a result of open-source collaboration through OpenJDK.
In traditional programming, source code is compiled into executable code. This executable code can run only on the platform it is intended to run. In other words, code written and compiled for Windows will only run on Windows, code written in Linux will only run on Linux, and so on.
A Java program, on the other hand, is compiled to byte code. You cannot run byte code by itself because it is not native code. Byte code can only run on a Java Virtual Machine (JVM). A JVM is a native application that interprets byte code. By making the JVM available on many platforms, Sun transformed Java into a cross-platform language. The very same byte code can run on any operating system for which a JVM has been developed.
- JVM: A Platform for Multiple Languages (slideshare.net)
- JavaOne 2012: Java Strategy Keynote and IBM Keynote (java.dzone.com)