code: public void addInitParam(final WebAppInitParam param) {
  		NullArgumentException.validateNotNull(param, "Init param");
  		NullArgumentException.validateNotNull(param.getParamName(),
  				"Init param name");
  		NullArgumentException.validateNotNull(param.getParamValue(),
  				"Init param value");
  		initParams.add(param);
  	}
docs: Add a init param for filter.
  
  @param param to be added
  @throws NullArgumentException if param, param name, param value is null