Each SLF4J log message contains a nested message

Question

I use JBoss 5.2 and whenever I log something, slf4j outputs a nested log message, e.g.

private final static Logger logger = LoggerFactory.getLogger(MyClass.class);

...

logger.info("FOOBAR")

will result in the log message:

2015-06-11 09:54:37,154 INFO  [STDOUT] (quartzScheduler_Worker-1) 09:54:37,154 INFO  [MyClass] FOOBAR

The inner message is the correct one, why does the outer say that the logging class is STDOUT?

Non-project classes (library-classes) log messages look fine e.g,

2015-06-11 09:54:16,538 FINE  [javax.activation] (quartzScheduler_Worker-1) MailcapCommandMap: load DEF

Here is my log4j settings file

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/" debug="false">    
    <appender name="FILE" class="org.jboss.logging.appender.DailyRollingFileAppender">
        <errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
        <param name="File" value="server.log"/>
        <param name="Append" value="true"/>
        <param name="Threshold" value="DEBUG"/>

        <param name="DatePattern" value="'.'yyyy-MM-dd"/>

        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d %-5p [%c] (%t) %m%n"/>
        </layout>
    </appender>

    <root>
        <priority value="DEBUG"/>
        <appender-ref ref="FILE" />
    </root>
</log4j:configuration>

Answer 1

I solved it by excluding JBoss version of slf4j. I still have multiple versions of SLF4J, but it seems to work.

2015-06-11 12:30:09,540 ERROR [STDERR] (main) SLF4J: Class path contains multiple SLF4J bindings.

To exclude JBoss slf4 I created the file WEB-INF/jboss-deployment-structure.xml with the contents:

<?xml version="1.0" encoding="UTF-8"?>
<jboss-deployment-structure>
    <deployment>
        <exclusions>
            <module name="org.slf4j" />
        </exclusions>
    </deployment>
</jboss-deployment-structure>

This site was very helpful http://ankitagarwal.com/wordpress/2012/05/20/using-your-own-instance-of-log4j-in-your-war-on-jboss-as-7-x-2/.