Overriding (or something similar) Exceptions

Hi guys,

We have a "legacy" Java application that has been developed by many
developers - some handle exceptions nicely, others not so.

What I would like to do is create a log of all the exceptions and
messages that are being thrown internally without changing the code.

I was thinking around the classloader - create my own Exception class
which uses the standard one but before passing the call to the standard
one, writes out to the log.

So mine is loaded by the JVM but all I do is extend the standard one
and override a method - is this "cyclic dependancy possible"?

If not, can anyone suggest any other route I could take to get the
desired functionality?

Cheers

Graham