me me me me -5 years ago 513
Java Question

java.lang.ClassFormatError: Incompatible magic value 218774561

Hey everyone I am making my first applet for java today. I have been using a subdomain at a server and I don't know what to do because I am getting this really weird error.

I have my jar in the server and everything but every time I try to load the Applet this happens.

java.lang.ClassFormatError: Incompatible magic value 218774561 in class file Evolution/EvolutionApplet

Upon research it appears that an incompatible magic value means that something has been corrupted in the .jar

Here is the website
the jars name is Evolution if you need the html code it is at the website.

Edit: The applet should be launched from Evolution.EvolutionApplet not Evolution.Evolution

Answer Source

The original problem seems fixed now. I could download the Jar from


It seems the Evolution.Evolution class is not an applet! Running it from the command line using:

java -jar Evolution.jar

Produces a frame (with a very 'retro' look)! As such, forget this applet nonsense, and launch the frame from a link using Java Web Start.

Old Answer

OTOH it now throws a ClassNotFoundException that (after inspecting the Jar) makes me think it should be:

<body bgcolor="#000000" text="#906060">
<applet code="Evolution.Evolution" archive="Evolution.jar" width="800" height="600">

There are two changes to the code attribute worth noting.

  1. The .class extension was removed. A minor matter, adding it is tolerated, but not correct.
  2. The Applet removed from the class name.
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