Question

I am trying to put log4j in a web application in Tomcat 7.
I have the log4j library in the WEB-INF\lib of my web application.
I have the following log4j.xml under WEB-INF\classes

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

    <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">

      <!-- Log output to Console -->
      <appender name="console" class="org.apache.log4j.ConsoleAppender"> 
        <param name="Target" value="System.out"/> 
        <layout class="org.apache.log4j.PatternLayout"> 
          <param name="ConversionPattern" value="%d [%t] %-5p %c - %m%n"/> 
        </layout> 
      </appender>  

      <appender name="rolling" class="org.apache.log4j.RollingFileAppender"> 
        <param name="file" value="myLogfile.log"/>    
        <param name="append" value="true" />
        <param name="encoding" value="UTF-8" />  
        <layout class="org.apache.log4j.PatternLayout"> 
          <param name="ConversionPattern" value="%d [%t] %-5p %c - %m%n"/> 
        </layout> 
      </appender> 

      <!-- Log to both Console and File -->
      <root> 
        <priority value ="debug" /> 
        <appender-ref ref="console" /> 
        <appender-ref ref="rolling" />
      </root>  
</log4j:configuration>

I log e.g. in a servlet or filter that I know are loading but I can not see the output log anywhere.

E.g.

Logger log = Logger.getLogger(MyFilter.class);

and in doFilter I log i.e. log.debug("logging information); log.error("logging information);

I can not see the output in the Tomcat console as a result of the console appender and I don’t see the myLogfile.log created either.

I am not sure where is this file supposed to be created.

I see only System.out statements from servlets and filters.

What am I doing wrong here?

UPDATE:
I have in the classpath xercesImpl.jar and jaxb-impl.jar. Could this cause an issue?

I noticed the following exception I missed earlier in Tomcat console:

log4j:WARN Error during default initialization
java.lang.NoClassDefFoundError: org/w3c/dom/ElementTraversal
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2823)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1160)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1655)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1533)
at org.apache.xerces.parsers.AbstractDOMParser.startDocument(Unknown
Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.startDocument(Unknown
Source)
at org.apache.xerces.impl.XMLDocumentScannerImpl.startEntity(Unknown
Source)
at org.apache.xerces.impl.XMLVersionDetector.startDocumentParsing(Unknown
Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
at org.apache.log4j.xml.DOMConfigurator$2.parse(DOMConfigurator.java:767)
at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:866)
at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:773)
at org.apache.log4j.helpers.OptionConverter.selectAndConfigure(OptionConverter.java:483)
at org.apache.log4j.LogManager.(LogManager.java:127)
at org.apache.log4j.Logger.getLogger(Logger.java:117)
at com.test.MyFilter.(MyFilter.java:26)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:125)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:256)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:382)
at org.apache.catalina.core.ApplicationFilterConfig.(ApplicationFilterConfig.java:103)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4624)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5281)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:866)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:842)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1095)
at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1617)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662) Caused by: java.lang.ClassNotFoundException: org.w3c.dom.ElementTraversal
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1688)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1533)
… 48 more

log4j:WARN No appenders could be found for logger (com.test.MyFilter).
log4j:WARN Please initialize the log4j system properly. log4j:WARN See
http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

Answer 1

Probably is only here, but you are missing the closing </log4j:configuration>

And for the file you can write this:

<param name="file" value="/usr/logs/myLogfile.log"/>

or

<param name="file" value="c:/logs/myLogfile.log"/>

How are you logging in your servlet classes? Put an example of the import and the sentences

I guess you are doing something like this, isnt?:

import org.apache.log4j.Logger;

private Logger log = Logger.getLogger(name);
log.debug("Mensaje de debug");

UPDATE:

The problem is a missing dependency in the class loader when trying to parse the Log4j XML, not a problem in the Log4j configuration.
The log shows that org/w3c/dom/ElementTraversal is missing. Having xercesImpl.jar already, the xml-apis.jar is needed

As stated here http://xerces.apache.org/xerces2-j/install.html the old xerces.jar contained all classes in one jar, but new distribution of xerces divides it in xercesImpl.jar and xml-apis.jar

Quoted:

xerces.jar is no longer available in the main distribution. You can still download this jar from deprecated distribution. xerces.jar is a Jar file that contains all the parser class files (i.e., it contains the intersection of the contents of xercesImpl.jar and xml-apis.jar).

To use another XML parser just remove xercesImpl.jar and add another implementation library. The problem was only the use of xercesimpl.jar without xml-apis.jar