JavaServer Pages, 3rd Edition

Using Java Applets

A Java applet is a Java class that is identified by a special element in an HTML page. The browser loads the class and executes it. An applet can provide a nice user interface on a web page. The problem is that the browsers don’t keep up with the Java release cycles for the native Java support. Many users still have browsers that support only JDK 1.0, and more current browsers have so many limitations and bugs in their implementations that you’re still limited to JDK 1.0 features to make the applet work.

To address this issue, Sun provides a Java runtime environment that can be integrated in a browser using the browser’s native plug-in API. The product is appropriately named the Java Plugin, and as of this writing the JDK 1.4 version is available for Netscape Navigator and Internet Explorer on Windows, Linux, and Solaris. For an up-to-date list of supported platforms, visit Sun’s Java Plugin page at http://java.sun.com/products/plugin/.

With the Java Plugin, you can use the latest Java features in your applets, such as the Swing GUI classes, collection classes, enhanced security, and more. But there’s one more hurdle you have to jump. The HTML element you need in a page to get the Java Plugin (or any plug-in component) installed and loaded by the browser differs between Internet Explorer and Netscape Navigator. For Netscape, you need to use the <embed> element, while Internet Explorer requires the <object> element. Fortunately, JSP provides an easy solution to ...