Question

I have an applet that will not load for 1 client who is running IE7 on Vista.

The error is:

java.lang.SecurityException: class "com.arup.web.printing.WebPrintApplet"'s signer information does not match signer information of other classes in the same package.

The applet code is in a jar file named: WebPrintApplet.jar and it has a dependency on Sun’s PdfRenderer.jar. I have signed both of the jar files with the same certificate and we are hosting the jar files from the same folder on our web server.

I am at a loss for what could cause this issue in our case. My applet’s code is all within the com.arup.web.printing.WebPrintApplet package and the entire jar file is signed.

Any clues as to the issue and how to resolve it?

Answer 1

I have signed both of the jar files with the same certificate and we are hosting the jar files from the same folder on our web server.

If one of the Jars was already signed, it will now have multiple digital signatures. That could cause the error seen.

As an aside, a Java 7 JRE should support deploying embedded applets using JWS, which in turn allows sand-boxed access to the printer. Here is a demo. or the JNLP PrintService.