INTRODUCTION TO JAVA

Java is an object oriented programming language with a built-in application programming interface (API) that can handle graphics and user interfaces and that can be used to create applications or applets. Because of its rich set of API’s, similar to Macintosh and Windows, and its platform independence, Java can also be thought of as a platform in itself. Java also has standard libraries for doing mathematics.

Much of the syntax of Java is the same as C and C++. One major difference is that Java does not have pointers. However, the biggest difference is that you must write object oriented code in Java. Procedural pieces of code can only be embedded in objects. In the following we assume that the reader has some familiarity with a programming language. In particular, some familiarity with the syntax of C/C++ is useful.

In Java we distinguish between applications, which are programs that perform the same functions as those written in other programming languages, and applets, which are programs that can be embedded in a Webpage and accessed over the Internet.

History

Java is a general purpose; object oriented programming language developed by Sun Microsystems of USA in 1991. Originally called Oak by James Gosling, one of the inventors of the language, Java was designed for the development of software for consumer electronic devices like TVs, VCRs, toasters and such other electronic machines. The goal had a strong impact on the development team to make the language simple, portable and highly reliable. The Java team which included Patrick Naughton discovered that the existing languages like C and C++ had limitations in terms of both reliability and portability.  However, they modelled their new language Java on C and C++ but removed a number of features of C and C++ that were considered as sources of problems and thus made Java a really simple, reliable, portable and powerful language. The most striking feature of the language is that it is a platform-neutral language. Java is the first programming language that is not tied to any particular hardware or operating system. Programs developed in Java can be executed anywhere on any system. Table 1.1 lists some important milestones in the development of Java.

YEAR	DEVELOPMENT
1990	Sun Microsystems decided to develop special software that could be used to manipulate consumer electronic devices. A team of Sun Microsystems programmers headed by James Gosling was formed to undertake this task.
1991	After exploring the possibility of using the most popular object-oriented language C++, the team announced a new language named “Oak”.
1992	The team, known as Green Project team  by Sun, demonstrated the application of their new language to control a list of  home appliances using a hand-held device with a tiny touch-sensitive screen.
1993	The World Wide Web (WWW) appeared on the Internet and transformed the text-based Internet into a graphically- rich environment. The Green Project team came up with the idea of developing Web applets (tiny programs) using the new language that could run on all types of computers connected to Internet.
1994	The team developed a Web browser called “HotJava” to locate and run applet programs on Internet. HotJava demonstrated the power of the new language, thus making it instantly popular among the Internet users.
1995	Oak was renamed “Java”, due to some legal snags. Java is just a name and is not an acronym. Many popular companies including Netscape and Microsoft announced their support to Java.
1996	Java established itself not only as a leader for Internet programming but also a general purpose, object oriented programming language. Sun releases Java Development Kit 1.0.
1997	Sun releases Java Development Kit 1.1 (JDK 1.1).
1998	Sun releases the Java2 with version 1.2 of the Software Development Kit (SDK 1.2).
1999	Sun releases the Java2 Platform, Standard Edition (J2SE) and Enterprise Edition (J2EE).
2000	J2SE with SDK 1.3 was released.
2002	J2SE with SDK 1.4 was released.
2004	J2SE with JDK 5.0 (instead of JDK) was released. This is known as J2SE 5.0.

Table 1.1 Versions of  java