How to refresh/reload UI in the vaadin 7.4.6


I have a issue to reload vaadin dashboard content with latest data. Im reading data from aws and building dashboard, but it load data only once. I want it should refresh it in every 5 seconds. I tried @Push(PushMode.AUTOMATIC), @Push(PushMode.MANUAL), @PreserveOnRefresh, Refresher addons.

I tried by "UI.getCurrent().accer(){}; method also but nothing is working fine. I tried to run thread to refresh navigator but no use it generate nullpointer exception. I am new in vaadin. Am I missing something.