code: public void registerHandler(String method, String url, OphApiHandler handler) {
  		if (mtdHandler == null)
  			mtdHandler = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
  
  		TreeMap<String, OphApiHandler> reg;
  		if (method == null)
  			method = "ALL";
  		reg = mtdHandler.get(method);
  		if (reg == null) {
  			reg = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
  			mtdHandler.put(method, reg);
  		}
  		reg.put(url, handler);
  	}
docs: register and handlet linked to a method
  
  @param method
  GET PUT POST DELETE or ALL
  @param url
  @param handler