libgcj/2237: serialization doesn't throw exception on failure

[Bryce McKinlay]

tromey@redhat.com wrote:

> >Description:
> When reading a serialized stream we should
> throw InvalidClassException if we don't recognize
> the data.  As far as I can tell we never do this.
> As an example see PR 1971.
> (If you want to use that test case you'll have
> to back out the fix first.)

This patch fixes it. It's dependent on some forthcoming fixes for
forName() etc...

regards

  [ bryce ]