Dynamically update text file in Java GUI
===

I have created JAVA GUI that will receive text file(.txt) from other client and append into the textarea(by using TextRecv.append) in Java Netbeans GUI however it doesn't read file that already sent from other client , I try to put readfile method in button perform however it read only when I push the button but that's not the result that I want, my target is make this GUI to dynamically receive file , read and append on to my text area automatically 

Any Suggestion?? Thank you for every advice