What is JAVA?

JAVA is a full programming language like pascal or C++. However, JAVA is object oriented and, as programmers, it forces us to adopt a more object oriented approach to writing programs than C++ does. JAVA syntax is close from the C++ one, which inspired the creators of the language.

JAVA programs take two forms; applications and applets. Applications are comparable to conventional programs written in C++. However, JAVA has powerful standard libraries that C++ don't. Let's name java.awt.*; which allows graphical interface and java.net.*; which allows network communications, internet for instance. Let's also note the java.lang.Thread class which makes JAVA a multi-threaded language. JAVA being compiled and then interpreted by a virtual machine, you only have to write the program once and it will run with any OS, but you have to make sure it does because implementations of the virtual machine may vary from one platform to another.

Applets are programs which runs inside a WEB page. An applet is called from a HTML document although it is possible to call it from an application. In that case, you have to use an alternative to the initial parameters passing mechanism.

Since most web browsers now have a JAVA virtual machine integrated, you only have to allow space, like you would for an image, to let an applet take full control of that space. Of course, since the code executes on the machine of the user who is looking at the page, this code must execute under severe restrictions. For instance, netscape won't let an applet read or write to the disk. However, some tools let you soften restrictions imposed to applets. See the applets page for examples of applets.

JAVA opens new possibilities for WEB design. It also constitutes an object oriented language which should be suited to develop large applications, relatively easy to maintain. For more details about the language see Hank Shiffman's article.