docs: public static ProtocolStackConfigurator getStackConfigurator(String properties) throws Exception {
          if(properties == null)
              properties=Global.DEFAULT_PROTOCOL_STACK;
  
          // Attempt to treat the properties string as a pointer to an XML configuration.
          XmlConfigurator configurator = null;
  
          checkForNullConfiguration(properties);
          configurator=getXmlConfigurator(properties);
  
          if(configurator != null) // did the properties string point to a JGroups XML configuration ?
              return configurator;
          throw new IllegalStateException(String.format("configuration %s not found or invalid", properties));
      }