Is Log4j being abandoned in favor of Slf4j? [closed]

Slf4j is indeed just a logging facade. However, Log4j is intended to be succeeded by Logback, from the very same authors.

Update: if you’d like to know about another benefit of Slf4j, it’s the fact that following (ugly) constructs aren’t needed anymore to avoid the toString() unnecessarily been called:

if (logger.isDebugEnabled()) {
    logger.debug("Message: " + bigObject + ", " + anotherBigObject);
}

You can instead make use of parameterized messages:

logger.debug("Message: {}, {}", bigObject, anotherBigObject);

Also see What is the fastest way of (not) logging?