In a previous project I switched from commons-logging -> log4j to sl4j -> logback. 
One of the reasons I did that was the overhead in log4j when providing a object in the log... 
log.debug("This is a object" + object); 
would cause the object.toString to be called even debug was not enabled. 

Now I work on a new project that uses commons-logging -> sl4j -> logback (jcl-over-slf4j) 

My question is now, will this still call object.toString.. even debug is not enabled 

import org.apache.commons.logging.Log; 
import org.apache.commons.logging.LogFactory; 
.... 
log.debug("This is a object" + object); 

I would like to get rid of commons-logging and jcl-over.sl4j and only have sl4j and logback.