Hi Kristian – yes, when adding two strings together, java does that automatically because the new concatenated string is the actual parameter you are passing, so it happens before you enter the log method. By using the varargs calling convention, the concatenation is postponed until after the method is entered.

Best regards,

From: logback-user-bounces@qos.ch [mailto:logback-user-bounces@qos.ch] On Behalf Of Kristian Lind
Sent: Thursday, February 07, 2013 4:36 PM
To: logback users list
Subject: Re: [logback-user] commons-logging -> sl4j -> logback

And that is of cause no matter if there is sl4j behind the commons-logging I guess ?

On Thu, Feb 7, 2013 at 1:11 PM, Brett Walker <brett.walker@geometryit.com> wrote:

With log.debug("The object is " + object), it will always call .toString() on object because the string argument needs to be constructed before the call to .debug().

To avoid this use either

If (log.isDebugEnabled()) {

Log.debug("The object is " + object);

}

Or the slf/logback usage

Log.debug("The object is {0}", object);

Which will delay the call to .toString() until it has determined that debug logging is needed.

Brett

Sent from my iPad

On 08/02/2013, at 7:43 AM, "Kristian Lind" <klpcrap@gmail.com> wrote:

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.

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--
Med venlig hilsen / Best regards

Kristian Lind