JSF Tip #28 - Turning logging on JSF up
Sometimes when you are working with JSF you might need to understand what is happening beneath the covers. It could be because you think a component is misbehaving and you want to make sure that is the case before you file a bug. To facilitate this you can turn the logging up and in Mojarra there are several loggers that you can use.
The following is a non-exhaustive list:
So say you want to see what the Flow subsystem is doing, well then you would set the logging for it to FINEST.
Note how your application server sets this depends on its implementation.