Java Applets and the Internet

The idea here is simple: Users will download Java bytecodes from the Internet and run them on their own machines. Java programs that work on web pages are called applets. To use an applet, you only need a Java-enabled web browser, which will execute the bytecodes for you. You need not install any software. Because Sun licenses the Java source code and insists that there be no changes in the language and standard library, a Java applet should run on any browser that is advertised as Java-enabled. You get the latest version of the program whenever you visit the web page containing the applet. Most important, thanks to the security of the virtual machine, you need never worry about attacks from hostile code.

When the user downloads an applet, it works much like embedding an image in a web page. The applet becomes a part of the page, and the text flows around the space used for the applet. The point is, the image is alive. It reacts to user commands, changes its appearance, and sends data between the computer presenting the applet and the computer serving it.