Why do we declare Loggers static final?

Question

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

private static final Logger S_LOGGER

Answer 1

According the the info I read from the internet about making the logger static or not, the best practice is to use it according to the use cases.

There are two main arguments:

1) When you make it static, it is not garbage collected (memory usage & performance).

2) When you don't make it static it is created for each class instance (memory usage)

Thus, When you are creating a logger for a singleton, you don't need to make it static. Because there will be only one instance thus one logger.

On the other hand, if you are creating a logger for a model or entity class, you should make it static not to create duplicated loggers.

Answer 2

This code is vulnerable，but, after Java7, we can use Logger lgr = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass()); instead of static logger.