It is not removed completely but there is next no performance impact due to branch prediction of the CPU.
Ideally you should use the logging level of the logger to determine whether the logger should be called.
Note: a simple method call like this has next to no overhead whether you check or not (and the library should check) Where you get a performance advantage is if you are doing something in the log message like
LOGGER.debug("The map is " + map);
In this case, the debug message will only be displayed if the debug is enable, however the string message will be build every time meaning this is more efficient.
if(LOGGER.isDebugEnabled())
LOGGER.debug("The map is " + map);