code: public void init(final FilterConfig filterConfig)
  		throws ServletException {
  		
  		// Get the init params
  		Properties props = getFilterInitParameters(filterConfig);
  		
  		// Extract and parse all required CORS filter properties
  		try {
  			config = new CORSConfiguration(props);
  			
  		} catch (CORSConfigurationException e) {
  		
  			throw new ServletException(e);
  		}
  		
  		handler = new CORSRequestHandler(config);
  	}
docs: This method is invoked by the web container to initialise the
  filter at startup.
  
  @param filterConfig The filter configuration.
  
  @throws ServletException On a filter initialisation exception.