Java Security

Hi,

I would like to sign a jar file from within my Java code. Reason for this is that I wish to update a jar file at runtime, throw away the class loader that loaded the jar, and load the updated code inside a new classloader.

One problem, however: The jar file has to be signed before loading it. How can I do this from my Java program? Or do I need to have the jarsigner tool available at the location where I resign the jar?

Thanks in advance,
Ronald.