1 jcl
and depends on the underlying log4j jcl jul, if it uses log4j log4j logging, use is not jul
spring5 underlying logging system relies on spring-jcl, and traditional jcl (common-logging.jar) are different, is a first attempt to add log4j2 ExtendedLogger inside, and then attempts to load slf4j SPI, is to try again if not loaded slf4j API jul,
So we intend to use to control the logging level must adopt log4j2 or slf4j. slf4j spi is slf4j extension, not very different.
Use slf4j and jcl as is common, but the use of slf4j need to add various log binder, in addition to their own logback realized binder, the rest will need to introduce additional jar package. slf4j document addresses http://www.slf4j.org/manual.html
There is the concept of a bridge slf4j systems bridged to the other log on slf4j, using a bridge when we must prevent circulation, http://www.slf4j.org/legacy.html document address.
