xml.properties: configuring the custom logger
log4j.logger.com.apress.logging.log4j=DEBUG, FILE log4j.appender.FILE=org.apache.log4j.FileAppender log4j.appender.FILE.File=xmlLayout.xml log4j.appender.FILE.layout=org.apache.log4j.xml.XMLLayout log4j.appender.FILE.layout.LocationInfo=true