Check if applet can load JNI library within the applet

Question

Hello,
I have a signed applet that is part of a bigger application. The application has native installer that installs some JNI libraries and grants permissions to my applet in java.policy file. However if the user did not install the application (using the installer) which means that the java.policy file is not modified. Then if he/she go directly go to the web UI, and opens my applet the user sees a dialog with the following warning: "The applet was signed by "xxx", but Java cannot verify the authenticity of the signature's certificate. Do you trust this certificate?" that have two buttons "Trust" and "Don't trust".
I have two questions:
A) Is it possible instead of showing the dialog, the JVM directly to choose "Don't trust", which means that I will get a security exception inside my code, so I can navigate to another site with installation instructions.
B) what is the exact reason for showing this dialog. Is it because I am calling System.loadLibrary("xxx"); which requires privileges. If this is the case, how can I check if the applet has enough privileges before calling System.loadLibrary()?
Thanks in advance
Kiril

Answer 1

A) Is it possible instead of showing the dialog, the JVM directly to choose "Don't trust", which means that I will get a security exception inside my code, so I can navigate to another site with installation instructions.Just don't sign it. It will be totally untrusted, except for clients that have java.policy modified.
You will get the exception, will catch it and you will be able to navigate to another page from the
catch block.
B) what is the exact reason for showing this dialog.The reason is that the applet is signed.
The reason for the "but..." part is that the certificate was created by a certificate authority that
Java does not recognize (it would recognize 'well known' CA's like Verisign, Thawte etc.).
Is it because I am calling System.loadLibrary("xxx"); which requires privileges. If this is the case, how can I check if the applet has enough privileges before calling System.loadLibrary()?Why 'before'? Isn't this good enough?
try
  System.loadLibrary("xxx");
  // Applet has privileges
catch ( SecurityException e )
  // Applet does not have privileges
}