How the logging is happening in this scenario

Question

I don't have a much knowledge in log4j and slf4j. But I want to understand how the actual logger is working in the below case.

I have a Web module,Service module and a Dao module.Web module has a dependency to Service and Service has a dependency to Dao .

In my web module there are 3 jars. slf4j jar, log4j jar and slf4j-log4j12 jar and log4j.xml is as below.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/" debug="true">
<!-- ============================== -->
   <!-- Append messages to the console -->
   <!-- ============================== -->

   <appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
      <errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
      <param name="Target" value="System.out"/>
      <param name="Threshold" value="INFO"/>

      <layout class="org.apache.log4j.PatternLayout">
         <!-- The default pattern: Date Priority [Category] Message\n -->
         <param name="ConversionPattern" value="%d{ABSOLUTE} %-5p [%c{1}] %m%n"/>
      </layout>
   </appender>

     <appender name="FILE" class="org.apache.log4j.DailyRollingFileAppender">        



        <param name="file" value="C:\\temp\\web.log" />
        <param name="DatePattern" value="'.'yyyy-MM-dd" />
        <layout class="org.apache.log4j.PatternLayout">
         <param name="ConversionPattern" value="[%t] %d{HH:mm:ss,SSS} %-5p %l - %m%n" />
        </layout>
    </appender>

<!-- ======================= -->
   <!-- Setup the Root category -->
   <!-- ======================= -->

   <root>
      <!-- 
         Set the root logger priority via a system property. Note this is parsed by log4j         
       -->
        <level value="trace" />
        <appender-ref ref="CONSOLE"/>
   </root>

   <logger name="com.mywork">
        <level value="DEBUG" />
        <appender-ref ref="FILE" />
    </logger>



    <logger name="org.hibernate">
        <level value="ERROR" />
        <appender-ref ref="FILE" />
    </logger>

     <logger name="org">
        <level value="ERROR" />
        <appender-ref ref="FILE" />
    </logger>

</log4j:configuration>

And In my service module and dao module contain only slf4j jar. And logging details are in file.(logging details of all modules)

Should the loggers of hibernate and Spring also available in my file ? How the exception occur are available in logger file?

Thank you

Vadzim Vadzim · Accepted Answer · 2013-10-11T06:25:16

You explicitly constrain org.* with ERROR level. This effectively eliminates almost all output of hibernate and spring loggers. But exceptions logged with error level should still get to file log.

Module dependencies configured in IDE are irrelevant. Logging happens in JBoss container and depends only on actual application's runtime classpath.

BTW, I highly recommend against trace level on root category. See Production settings file for log4j? for the explanation.

How the logging is happening in this scenario

1 Answers