slf4j: debug behavior inconsistent?

I'm using slf4j + log4j with a library of mine.

I am using it in a quick application where I don't really care about configuring the logging... or at least I didn't think I cared.

If I don't configure log4j, I get the standard warning message

log4j:WARN No appenders could be found for logger com.xyz.abcdbabble
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for开发者_JAVA技巧 more info.

which is fine. If I then do

logger.debug("Blah blah blah")

then the logger doesn't print anything out. Great!

But if I do

if (logger.isDebugEnabled())
{
    System.out.println("print some complex stuff:");
    print_some_complex_stuff();
}

then the stuff in brackets gets executed. What gives?

I'm looking for a way to determine whether to print out something that should have an equivalent enabling to logger.debug(), even if log4j isn't configured in the end application. How can I do this?

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Instead of trying to figuring out the logic of the log4j default configuration, I would put in a config file (log4j.properties), like:

log4j.rootLogger=debug, console
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d %5p [%t] (%F:%L) - %m%n

At least this puts you into control.

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Instead of bundling with log4j then bundle with the "simple" backend from the slf4j distribution. Then things work as you want them to, and the users cannot tinker.