Why do we declare Loggers static final?

In Java, why is it best practice to declare a logger static final?

private static final Logger S_LOGGER

Solution 1:

• private - so that no other class can hijack your logger
• static - so there is only one logger instance per class, also avoiding attempts to serialize loggers
• final - no need to change the logger over the lifetime of the class

Also, I prefer name log to be as simple as possible, yet descriptive.

EDIT: However there is an interesting exception to these rules:

protected final Logger log = LoggerFactory.getLogger(getClass());

as opposed to:

private static final Logger log = LoggerFactory.getLogger(Foo.class);

The former way allows you to use the same logger name (name of the actual class) in all classes throughout the inheritance hierarchy. So if Bar extends Foo, both will log to Bar logger. Some find it more intuitive.

Solution 2:

Check this blog post: Get Rid of Java Static Loggers. This is how you use slf4j with jcabi-log:

import com.jcabi.log.Logger;
class Foo {
  void save(File f) {
    Logger.info(this, "file %s saved successfully", f);
  }
}

And never use that static noise any more.