Why was the TRACE level introduced only in SLF4J version 1.4.0?
The addition of the TRACE level has been frequently and hotly debated request. By studying various projects, we observed that the TRACE level was used to disable logging output from certain classes without needing to configure logging for those classes. Indeed, the TRACE level is by default disabled in log4j and logback as well most other logging systems. The same result can be achieved by adding the appropriate directives in configuration files. Thus, in many of cases the TRACE level carried the same semantic meaning as DEBUG. In such cases, the TRACE level merely saves a few configuration directives. In other, more interesting occasions, where TRACE carries a different meaning than DEBUG, Marker objects can be put to use to convey the desired meaning. However, if you can’t be bothered with markers and wish to use a logging level lower than DEBUG, the TRACE level can get the job done. Note that while the cost of evaluating a disabled log request is in the order of a few nanoseconds, t
