public void addClasses(List<String> classNames){
  if (handlerFactories == null) {
    handlerFactories=new ArrayList<String>();
  }
  handlerFactories.addAll(classNames);
}

public void addClasses ( List < String > classNames ) { if ( handlerFactories == null ) { handlerFactories = new ArrayList < String > ( ) ; } handlerFactories . addAll ( classNames ) ; }
add a list of exception handler class names .
