When logging a message there are two important requirements which must be fulfilled:

• The user must be able to easily retrieve the logs
• The format of all logged message must be uniform to allow the user to easily read the log

If a program directly writes to the standard outputs, there is absolutely no way to comply with those requirements. That's why defining and using a dedicated logger is highly recommended.

The following code snippet illustrates this rule:

System.out.println("My Message");  //Non-Compliant

logger.log("My Message");          //Compliant