In theory, Java programs are "write once, run everywhere." In practice, Java programs are somewhat less platform dependent than other programs, but they are still platform dependent. Java programs that run under a web browser, like Netscape or Internet Explorer, are called applets. Whether an applet runs correctly depends on the version of the browser, the operating system, the version of the operating system, and even the hardware configuration. Collectively, all these parameters are called the platform.
The applets included on the web pages for this course have been tested with a very limited number of platforms. This page is intended to help you diagnose problems. Please send email to email@example.com if you find errors or can suggest additions to this page.
If your browser does not support JDK 1.1, you might see the following message in your Java console window (which you can open under Netscape's "Communicator" menu):
# Applet exception: error: java.lang.NoSuchMethodError: java.awt.TextArea: method <init> (Ljava/lang/String;III)V not found
Unfortunately, the Java virtual machine often produces some pretty useless error messages. For example, "class not found" could mean almost anything. It roughly translates as "something went wrong."
Under Windows NT (4.0), open the Start menu (at the lower left), select Settings and then Control Panel. Open the System control panel, and click on the Environment tab. If the CLASSPATH variable is set, we suggest clearing it (you may want to save its value, since it may be needed by some other program). You then probably have to restart your browser.
More information about JDK 1.1 compatible browsers.