Lesson: Java Applets

This lesson discusses the basics of Java applets, how to develop applets that interact richly with their environment, and how to deploy applets.

A Java applet is a special kind of Java program that a browser enabled with Java technology can download from the internet and run. An applet is typically embedded inside a web page and runs in the context of a browser. An applet must be a subclass of the java.applet.Applet class. The Applet class provides the standard interface between the applet and the browser environment.

Swing provides a special subclass of the Applet class called javax.swing.JApplet. The JApplet class should be used for all applets that use Swing components to construct their graphical user interfaces (GUIs).

The browser's Java Plug-in software manages the lifecycle of an applet.

Use a web server to test the examples in this lesson. The use of local applets is not recommended, and local applets are blocked when the security level setting in the Java Control Panel is set to High or Very High.


Note: Some features of Java applets may not work as described on Mac OS. This is because of the way the Java Plug-in software interfaces with browsers on Mac OS.

Note:  Please make sure you have at least Java SE Development Kit (JDK) 6 update 10 release on your client machine before proceeding further. You will need this to view the sample rich internet applications and read subsequent sections without interruptions.