Introduction

[Note: This chapter and its exercises are intentionally small and simple for readers who wish to learn about applets after reading only the first few chapters of the bookpossibly just Chapters 2 and 3. We present more complex applets in Chapter 20, Multimedia: Applets and Applications, Chapter 23, Multithreading and Chapter 24, Networking.]

This chapter introduces appletsJava programs that can be embedded in HyperText Markup Language (HTML) documents (i.e., Web pages). When a browser loads a Web page containing an applet, the applet downloads into the Web browser and executes.

The browser that executes an applet is generically known as the applet container. The JDK includes the appletviewer applet container for testing applets as you develop them and before you embed them in Web pages. We typically demonstrate applets using the appletviewer. If you would like to execute your applets in a Web browser, be aware that some Web browsers do not support J2SE 5.0 by default. You can visit java.com and click the Get It Now button to install the J2SE Runtime Environment (JRE) 5.0 for your browser. Several popular browsers are supported.