code: protected void initAdditionalPropertyBaseNames(ServletContext context) {
  		String propertyNames = context.getInitParameter(SERVLET_CONTEXT_ADDITIONAL_CONFIG_PARAM);
  		propertyBaseNames = new ArrayList<>();
  		if (null != propertyNames) {
  			StringTokenizer tk = new StringTokenizer(propertyNames, ",");
  			while (tk.hasMoreTokens())
  				propertyBaseNames.add(tk.nextToken());
  		}
  	}
docs: Initializes the propertyBaseNames list by reading the jawr.config.sources
  servlet context param. Subclasses may override this method to use a
  different strategy.
  
  @param context