code: public void addSipApplicationListener(String listener) {
      	if(logger.isDebugEnabled()) {
  			logger.debug("addSipApplicationListener " + getName());
  		}
  
      	sipApplicationListeners.add(listener);
      	fireContainerEvent("addSipApplicationListener", listener);
  
          // FIXME - add instance if already started?
  
      }
docs: Add a new Listener class name to the set of Listeners
  configured for this application.
  
  @param listener Java class name of a listener class