title: Intercept Log Messages slf4j
body: <p>I have an application which uses slf4j as the logging facade. Now I would like to intercept all the error messages before the transfer is handed out to the underlying logging system. Is it possible to do that for slf4j? I looked through the documentation and see that we can change the Appenders in the implementation (like log4j) to achieve this but can we do this at the facade level itself? The intercept does basic stuff like incrementing a global counter for the number of error messages etc.</p>