java - Logger vs. System.out.println

Question

I'm using the PMD plugin for eclipse and it gives me an error when using System.out.println() with the explanation:

System.(out|err).print is used, consider using a logger.

My question is - What is a Logger? How is it used to print to the screen? Why is it better?

Answer 1

See this short introduction to log4j.

The issue is in using System.out to print debugging or diagnostic information. It is a bad practice because you cannot easily change log levels, turn it off, customize it, etc.

However if you are legitimately using System.out to print information to the user, then you can ignore this warning.