Yes, simply add log4j.debug to the JVM system variables. For example:
java -Dlog4j.debug -cp ... some.class.name
Log4j will then output something like the following:
log4j: Trying to find [log4j.xml] using context classloader sun.misc.Launcher$AppClassLoader@1f7182c1.
log4j: Using URL [file:/C:/Users/matt/workspace/projectname/target/test-classes/log4j.xml] for automatic log4j configuration.
log4j: Preferred configurator class: org.apache.log4j.xml.DOMConfigurator
log4j: System property is :null
log4j: Standard DocumentBuilderFactory search succeded.
log4j: DocumentBuilderFactory is: org.apache.xerces.jaxp.DocumentBuilderFactoryImpl
log4j: debug attribute= "null".
log4j: Ignoring debug attribute.
log4j: reset attribute= "false".
log4j: Threshold ="null".
...
For reference see the manual and the FAQ.