Well, I am using the vaadin AppletIntegration Addon to integrate my sound recorder applet with my vaadin project. Here is the code :

Java Code:
 AppletIntegration applet = new AppletIntegration() {

    private static final long serialVersionUID = 1L;

    public void attach() {
      System.out.println("In attach functions");

      setAppletArchives(Arrays.asList(new String[] { "SoundRecordingJar.jar" }));

When I run it in browser : It gives me the following exception:

java.lang.ClassFormatError: Incompatible magic value 1008813135 in class file AudioApplet
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(Unknow n Source)
at sun.plugin2.applet.Applet2ClassLoader.findClass(Un known Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(U nknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Un known Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Un known Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unk nown Source)
at sun.plugin2.applet.Plugin2Manager.initAppletAdapte r(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionR unnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

If I run the same applet with html file, it works fine with no exception. The applet is signed also.

So, What does this error mean and how to solve it.