This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
The wait method is used to synchronize threads, not to delay a user interface update. What you want to do would look more like this:
This example does not consider threading. If this were done in swing, for instance, you'd want to run the entire method on a worker and dispatch showAdvertisement() and hideAdvertisement() on the EDT, but i guess this is going too much into detail.