a simple examples cannot work.

i m a beginner learning jsp.
i tried this code ,but when i open the web, i found a error , click on the applet it says:program cannot run .

load：cannot find class Clock2.class。
java.lang.ClassNotFoundException: Clock2.class
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
exception：java.lang.ClassNotFoundException: Clock2.class

code:

<html>
<title> Plugin example </title>
<body bgcolor="white">
<h3> Current time is : </h3>
<jsp:plugin type="applet" code="Clock2.class" codebase="applet" jreversion="1.2" width="160" height="150" >
<jsp:fallback>
Plugin tag OBJECT or EMBED not supported by browser.
</jsp:fallback>
</jsp:plugin>
<p>
<h4>
<font color=red>
The above applet is loaded using the Java Plugin from a jsp page using the
plugin tag.
</font>
</h4>
</body>
</html>

my computer's environment variables has already done.

If I'm not mistaken, the way you wrote that HTML code means that the applet class (Clock2.class) must be in the same folder as the HTML file on the server. That's assuming that the class isn't in a package, which is also what the HTML implies.