display the arraylist data on UI as soon as something is added using java -

what trying implementing news feeds kind of functionality.. have listener call function posted user , function give me post , store in arraylist..

now want display post on ui.. can't find perfect way this.. don't want call method or send request every 5 or 10 seconds ui contents in list.. want list updated new post, should displayed on ui..

please me on , let me know if there additional information required..