Java is a computer programming language created by Sun Micro systems. Java is used mainly on the Internet and uses a virtual machine which has been implemented in most browsers to translate Java into a specific application on different computer system. With most programming languages, you either compile or interpret a program so that you can run it on your computer. The Java programming language is unusual in that a program is both compiled and interpreted.
The most common Java programs are applications and applets. Applications are standalone programs, such as the HotJava browser. Applets are similar to applications, but they don’t run standalone. Instead, applets adhere to a set of conventions that lets them run within a Java-compatible browser. Java (with a capital J) is a high-level, third generation programming language, like C, Fortran, Smalltalk, Perl, and many others. You can use Java to write computer applications that crunch numbers, process words, play games, store data or do any of the thousands of other things computer software can do. Compared to other programming languages, Java is most similar to C. However although Java shares much of C’s syntax, it is not C. Knowing how to program in C or, better yet, C++, will certainly help you to learn Java more quickly, but you don’t need to know C to learn Java. Unlike C++ Java is not a superset of C. A Java compiler won’t compile C code, and most large C programs need to be changed substantially before they can become Java programs.
What’s most special about Java in relation to other programming languages is that it lets you write special programs called applets that can be downloaded from the Internet and played safely within a web browser. Traditional computer programs have far too much access to your system to be downloaded and executed willy-nilly. Although you generally trust the maintainers of various ftp archives and bulletin boards to do basic virus checking and not to post destructive software, a lot still slips through the cracks. Even more dangerous software would be promulgated if any web page you visited could run programs on your system. You have no way of checking these programs for bugs or for out-and-out malicious behavior before downloading and running them. Java solves this problem by severely restricting what an applet can do. A Java applet cannot write to your hard disk without your permission. It cannot write to arbitrary addresses in memory and thereby introduce a virus into your computer. It should not crash your system.
A platform is a loosely defined computer industry buzzword that typically means some combination of hardware and system software that will mostly run all the same software. For instance PowerMacs running Mac OS 9.2 would be one platform. DEC Alphas running Windows NT would be another. There’s another problem with distributing executable programs from web pages. Computer programs are very closely tied to the specific hardware and operating system they run. A Windows program will not run on a computer that only runs DOS. A Mac application can’t run on a Unix workstation. VMS code can’t be executed on an IBM mainframe, and so on. Therefore major commercial applications like Microsoft Word or Netscape have to be written almost independently for all the different platforms they run on. Netscape is one of the most cross-platform of major applications, and it still only runs on a minority of platforms. Java solves the problem of platform-independence by using byte code. The Java compiler does not produce native executable code for a particular machine like a C compiler would. Instead it produces a special format called byte code. Java byte code written in hexadecimal, byte by byte. For more information you can mail us at mail~at~softwaredevelopmentcompany.co.in.