code: public void addTo(String address, String personal) throws AddressException {
  		if(to == null) {
  			to = new ArrayList<>();
  		}
  		to.add( toInternetAddress(address, personal) );
  	}
docs: adds a recipient (To)
  
  @param address a valid email address
  @param personal the real world name of the sender (can be null)
  @throws AddressException in case of an invalid email address