code: private void handleInvalidCORS(final HttpServletRequest request, final HttpServletResponse response, final FilterChain filterChain) {
  		String origin = request.getHeader(CorsFilter.REQUEST_HEADER_ORIGIN);
  		String method = request.getMethod();
  		String accessControlRequestHeaders = request.getHeader(REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS);
  
  		response.setContentType("text/plain");
  		response.setStatus(HttpServletResponse.SC_FORBIDDEN);
  		response.resetBuffer();
  
  		if (log.isDebugEnabled()) {
  			// Debug so no need for i18n
  			StringBuilder message = new StringBuilder("Invalid CORS request; Origin=");
  			message.append(origin);
  			message.append(";Method=");
  			message.append(method);
  			if (accessControlRequestHeaders != null) {
  				message.append(";Access-Control-Request-Headers=");
  				message.append(accessControlRequestHeaders);
  			}
  			log.debug(message.toString());
  		}
  	}
docs: Handles a CORS request that violates specification.
  
  @param request
  The {@link HttpServletRequest} object.
  @param response
  The {@link HttpServletResponse} object.
  @param filterChain
  The {@link FilterChain} object.