code: private void configureProcessName() throws XPathExpressionException {
  		if (processName != null) {
  			return;
  		}
  		processName = "";
  		Node jvm = getXmlNode("/jmxetric-config/jvm", inputSource);
  		if (jvm != null) {
  			processName = jvm.getAttributes().getNamedItem("process")
  					.getNodeValue();
  		}
  	}
docs: The XML file may specify a processName to be used, which can be different
  from the one used in the constructor. The name in XML takes priority.
  
  @throws XPathExpressionException