Ivor Horton's Beginning Java™ 2, JDK™ 5th Edition

1.1. What Is Java All About?

Java is an innovative programming language that has become the language of choice for programs that need to run on a variety of different computer systems. First of all, Java enables you to write small programs called applets. These are programs that you can embed in web pages to provide some intelligence. Being able to embed executable code in a web page introduces a vast range of exciting possibilities. Instead of being a passive presentation of text and graphics, a web page can be interactive in any way that you want. You can include animations, games, interactive transaction processing—the possibilities are almost unlimited.

Of course, embedding program code in a web page creates special security requirements. As an Internet user accessing a page with embedded Java code, you need to be confident that it won't do anything that might interfere with the operation of your computer, or damage the data you have on your system. This implies that execution of the embedded code must be controlled in such a way that it will prevent accidental damage to your computer environment, as well as ensure that any Java code that was created with malicious intent is effectively inhibited. Java implicitly incorporates measures to minimize the possibility of such occurrences arising with a Java applet.

Java's support for the Internet and network-based applications generally doesn't end with applets. For example, Java Server Pages (JSP) provides a powerful means of building ...