logging - What is the difference between Java Logger and System.out.println

Question

I looked up the api about the logger class(here) and I was looking at the Logger.info method. I was confused when I saw its perimeter as a message displayed as a string public void info(String msg) which is same as System.out.println(). I am wondering what is the different between these two, and why do we use Logger instead of System.out.println when they can print out the same thing.

In Logger.

Logger.info("Hello")

Output:

[INFO ] 2015-08-07 11:18:46.140 [main] ClassName Hello

In System.out.println

`System.out.println("Hello")

Output: Hello

Answer 1

Usually, because a Logger can be configured to write to a file (and the console). It might also be configured at higher (or lower) granularity as to messaging. For example, you might configure (at runtime) for level of warn. In which case, that logger would not display debug or info messages. It can include information such as the class that is writing, a line number, and a date and time (of the message).