1. What can cause a "class file not found" message?

Symptoms: Error messages in the browser like those below, a browser that times out or appears to hang, or a gray box that appears where the applet should be.

Summary: The browser behavior is somewhat unpredictable when the <applet> markup is incorrect, or the class files are not where they should be, or do not have the correct names (including capitalization). If the server is very slow, a Java applet time out may cause similar messages.

SAMPLE MESSAGES:

(Java Console) Applet exception: class hm could not be loaded
or  
(Netscape) Applet hm class hm could not be loaded
or  
(Internet Explorer) load: class hm not found

 

This problem is encountered when

  1. The <applet> tag in the HTML does not match the actual locations of the Java class files.

  2. The class files' case sensitive names have changed since installation. This may happen, for example, when they are FTP'd to the server.


Check the following:

File Locations

    All Java and .mvr files must be located on the same server. This is a Java requirement.

Case Sensitivity

    The names of the class files must not change from the installation package. (Please see the installation instructions for the latest set of class names. This problem might occur when files have been moved from a Windows to a UNIX server, as case sensitivity is typically different between these environments. When in doubt, be sure to verify the names of the class files, or reload the appropriate source (.zip, .tar, etc.) for the server.

Codebase errors (HTML applet tag)

The CODEBASE tag describes the location of the directory that contains the class files. This can be expressed in either of two ways:

  1. As the location of the class files relative to the HTML (if the HTML is on the same server as the class files) or


  2. As the absolute URL of the class files directory. (This can be used when the HTML and class files are on the same or different servers.)

Code (HTML applet tag)

This should always be CODE="hm.class".

Value (HTML applet tag)

This is the path and name of the .mvr file relative to the directory in CODEBASE.

If the directory to which CODEBASE points, or the specification of CODE or Value is incorrect, the not found error may occur.

Please see the installation guide for detailed instructions on how to prepare the HTML.