Issue while starting WLDF Console Extension

Any fix to avoid this exception while starting WLDF Console? Thanks.

java.lang.ClassFormatError: Incompatible magic value 218762506 in class file com/bea/diagnostics/dashboard/ChartPanelApplet
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(Unknown Source)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    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.ClassFormatError: Incompatible magic value 218762506 in class file com/bea/diagnostics/dashboard/ChartPanelApplet

Solution

There is an earlier Sun bug report on this issue, with JDK 1.4

you are mostly running JDK 1.6 but take a look at the bug report.

Short Summary (gleaned from this forum) :

The Java plug-in of your browser tries to get some .class file from the current location (your server) and fails because your server returns some custom 404 page. Let's try to check the Java console to see what really is requested. Please, run the Java console, set the trace level to 5 (highest level).

Enable the Java console on Windows for IE browser and see if it gives a detail on which URL is giving the 404 or some other error.

Further Reading

Oracle forum question