Log4J: Strategies for creating Logger instances

Question

I decided to use Log4J logging framework for a new Java project. I am wondering what strategy should I use for creating/managing Logger instances and why?

Answer 1

• Create one logger per class.
• If you have dependencies that require Commons Logging (quite likely) use slf4j's bridge for Commons Logging. Instantiate your loggers (per class) using the Commons Logging interface: private static final Log log = LogFactory.getLog(MyClass.class);
• Manifest this pattern in your IDE using shortcuts. I use IDEA's live templates for this purpose.
• Provide contextual information to threads using an NDC (thread local stack of strings) or an MDC (thread local map of String → ?).

Examples for templates:

private static final Log log = LogFactory.getLog($class$.class); // live template 'log'

if (log.isDebugEnabled())
    log.debug(String.format("$string$", $vars$)); // live template 'ld', 'lw', 'le' ...