Note this blog is obsolete, see https://www.manorrock.com/blog/ for the current blog Sometimes when you are working with JSF you might need to understand what is happening beneath the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: 
  • application
  • application.view
  • resource
  • config
  • context
  • facelets.compiler
  • facelets.tag.component
  • facelets.el
  • facelets.tag.meta
  • facelets.tag.ui.composition
  • facelets.tag.ui.decorate
  • facelets.tag.ui.include
  • faclets.facelet
  • facelets.factory
  • flow
  • ifecycle
  • managedbean
  • renderkit
  • taglib
  • timing
  • util
  • flash
So say you want to see what the Flow subsystem is doing, well then you would set the logging for it to FINEST. 
 javax.enterprise.resource.webcontainer.jsf.flow=FINEST
Note how your application server sets this depends on its implementation. Enjoy!