Logging is a mechanism of keeping track of the runtime behavior of an application, mainly for debugging / tracing purposes. In almost all of significantly complex / vital applications, maintaining a proper application log is a must; hence, almost all developers are quite familiar with the paradigm of logging. And it isn’t rocket science. You just have to call a simple method with whatever you want to log, and mess around with a simple configuration file, and that’s all. So what’s the big deal?
The problem is that though logging is a simple thing to do, doing it correctly needs a lot of practice, experience and understanding. That makes it more of an art than a science. In my personal experience, mastering the art of logging requires lots of patience, experience and forward thinking. It’s quite difficult to teach someone how to do it (sort of tacit knowledge), and most freshers tend to see the effort put into writing to log files as something additional. But all that effort pays up when you go through long nights trying to figure out what went wrong in a production system. But for that, it is important that proper logging is done through-out the system, which requires all of the team to master this dark art. Just one guy doing it right in a team is simply not enough.