threads server or client side


I have a simple question, but I need an answer: For example the progress indication.

Is the “work thread” in the example running on the server side or client side?

What happens, if the thread is running (you need an user interaction to interrupt the thread) and the user closes the window(gui). The user has not stopped the thread and the thread will continue to infinity?

I ask myself that because: When I close my portlet by closing the subwindow of the application (liferay and vaadin), then the thread is still alive.