Internet data plan is costing you too much money? Want to restrict certain Android application from accessing Internet? DroidWall is the Android firewall application that you need. It helps to block Internet access for the application that you selected (black list). And it can help to improve battery life too with lesser Android application accessing data connection. Besides, it can block advertisements too. The best part, it helps to stop certain Android applications or games from grabbing your privacy data through Internet. By the way, root access is required.