Show waiting icon (loading icon) while running thread

Hi
My Vaadin applicaiton (I am using vaaadin 7.3.8) use a Runnable object to select a lot of data from a databse. Once this is done data is injected to UI through push mechanism (using the access method). Object selection task from database takes around 2 min. How can I show the loading icon for the user to inform him to wait for data ??

Thanks for helping.