Hi all, I'm seriousely tearing my hair off with jboss 4.0.5 classloding problems We're trying to migrate from jboss 4.0.3.SP1 to jboss 4.0.5. About 10 applications are concerned (all of them are ears) and each of them have their loader repository defined like below in jboss-app.xml file Each application has it own log4j.jar <jboss-app> <loader-repository>nis_portail:loader=my_appXloader</loader-repository> </jboss-app> When we start Jboss after putting webapps in deploy directory. We're getting the error messages below: log4j:ERROR A "org.jboss.logging.util.OnlyOnceErrorHandler" object is not assignable to a "org.apache.log4j.spi.ErrorHandler" variable. log4j:ERROR The class "org.apache.log4j.spi.ErrorHandler" was loaded by log4j:ERROR [org.jboss.mx.loading.UnifiedClassLoader3@7f30f8{ url=file:/D:/Documents/developpements/workspace/nis_portail_ear/deploy/portail_ear.ear/ ,addedOrder=48}] whereas object of type log4j:ERROR "org.jboss.logging.util.OnlyOnceErrorHandler" was loaded by [org.jboss.system.server.NoAnnotationURLClassLoader@1a33d48]. log4j:ERROR Could not create an Appender. Reported error follows. java.lang.ClassCastException: org.jboss.logging.appender.DailyRollingFileAppender at org.apache.log4j.xml.DOMConfigurator.parseAppender(DOMConfigurator.java:165) at org.apache.log4j.xml.DOMConfigurator.findAppenderByName(DOMConfigurator.java:140) at org.apache.log4j.xml.DOMConfigurator.findAppenderByReference(DOMConfigurator.java:153) at org.apache.log4j.xml.DOMConfigurator.parseChildrenOfLoggerElement(DOMConfigurator.java:415) at org.apache.log4j.xml.DOMConfigurator.parseRoot(DOMConfigurator.java:384) at org.apache.log4j.xml.DOMConfigurator.parse(DOMConfigurator.java:783) at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:666) at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:616) at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:602) at org.apache.log4j.helpers.OptionConverter.selectAndConfigure(OptionConverter.java:460) at org.apache.log4j.LogManager.(LogManager.java:113) at org.apache.log4j.Logger.getLogger(Logger.java:85) I've seen in the forum that a solution to solve this problem is to remove log4j.jar from application librairies. I would like to know if there is not another solution because some applications MUST use spécific log4j.jar versions to log properly. And all theses application worked fine with JBoss4.0.3SP1 Any suggestion would be greatly appreciated. Meissa View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4031090#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...