The topmost layer in the Android stack consists of applications (called apps), which are programs that users directly interact with. There are two kinds of apps, as discussed here:
- System apps: These are applications that are pre-installed on the phone and are shipped along with the phone. Applications such as default browser, email client, and contacts are examples of system apps. These generally cannot be uninstalled or changed by the user as they are read-only on production devices, though some devices offer the ability to disable these applications. If a system application is disabled, the app and all of its data remain on the device on the system partition, the application icon is simply hidden from the user. These ...