Marvin applet - Incompatible Magic Value error

Hello,





I am in the process of moving one of our existing applications to a new server in a DMZ for external access. The application is in .NET and I have configured everything to get the .NET pages to work correctly.





The initial page uses the Marvin sketch applet. I have not changed any of the parameters for calling the applet, but when I run it I get the following stack trace error:





java.lang.ClassFormatError: Incompatible magic value 1008813135 in class file JMSketch


at java.lang.ClassLoader.defineClass1(Native Method)


at java.lang.ClassLoader.defineClass(Unknown Source)


at java.security.SecureClassLoader.defineClass(Unknown Source)


at sun.applet.AppletClassLoader.findClass(Unknown Source)


at java.lang.ClassLoader.loadClass(Unknown Source)


at sun.applet.AppletClassLoader.loadClass(Unknown Source)


at java.lang.ClassLoader.loadClass(Unknown Source)


at sun.applet.AppletClassLoader.loadCode(Unknown Source)


at sun.applet.AppletPanel.createApplet(Unknown Source)


at sun.plugin.AppletViewer.createApplet(Unknown Source)


at sun.applet.AppletPanel.runLoader(Unknown Source)


at sun.applet.AppletPanel.run(Unknown Source)


at java.lang.Thread.run(Unknown Source)





I have tried this with the original version of jmarvin.jar (4.1.6) which was being used and also with a newer version (4.1.12), both versions give the same error.





Any help would be appreciated.





Cheers


Paul

An update - this may be due to our internal Webmarshal / Big Brother style internet usage regulator program, examining the jar file and sending a html error page instead of the jar to the browser, but this is unconfirmed for now. If it is the cause, I will update here.





Thanks to those people who've looked at this so far.


Paul

I do not know Webmarshal but as you descibe it, I can imagine that it can cause the problem.


The stack trace indicate that the jar is damaged somehow (maybe at downloading). So the Java can not read it in properly.





Do you use a Sun distributed Java version? I can also imagine that a non-Sun-compatible Java can drop such misterious exception.

Just in case anyone encounters this problem in the future, it was due to the company's internet filtering software not allowing users to download executable files - the jar from the applet was not getting through properly.





Hope this helps someone out.


Paul