Log4J fails to initialize in an isolated deployment

Issue

• A deployment that configures an isolated Log4J environment throwing the following error upon deployment. Why is this happening and how to fix it?

log4j:ERROR A "org.apache.log4j.xml.DOMConfigurator" object is not assignable to a "org.apache.log4j.spi.Configurator" variable.
log4j:ERROR The class "org.apache.log4j.spi.Configurator" was loaded by
log4j:ERROR [BaseClassLoader@2fecdb1b{vfszip:/app/jboss-eap-5.1.2/jboss-as/server/default/deploy//your-deployment.ear/}] whereas object of type
log4j:ERROR "org.apache.log4j.xml.DOMConfigurator" was loaded by [BaseClassLoader@2bc68b6f{vfsfile:/app/jboss-eap-5.1.2/jboss-as/server/default/conf/jboss-service.xml}].
log4j:ERROR Could not instantiate configurator [org.apache.log4j.xml.DOMConfigurator].
log4j:WARN No appenders could be found for logger (some.class.that.uses.log4j.ClassName).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

• How the log4j is related to the logging subsystem in standalone.xml file ?