Re: Unsealing a jar file at runtime
On Jul 28, 4:21 am, Andreas Leitgeb <a...@gamma.logic.tuwien.ac.at>
wrote:
raph...@gmail.com <raph...@gmail.com> wrote:
I don't suppose that this is possible, perhaps with reflection?
The idea is for a plugin to extend a class, but the class is not a
public class, so can only be extended from within the same package.
If the jar file was unsealed, then a class could be created within the
plugin that is in the same package, is public and extends the non-
public class.
Breaking open a seal is typically easily done.
Reinstating someone else's seal on the changed
content is "believed" to be much harder. I also
believe that it is, but I'm no crypto-expert.
Even were you to succeed in extending the package-private class and
making it public, there are gotchas. The parent class (the one
already in the JAR) could make assumptions of package-private
visibility that a public subclass would break, e.g., exposure of
package-private methods or attributes for use by its putative friends.
--
Lew
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