Android Security Model
On Android each app does only have access to its own data. Each app belongs to a single user. Each application
has an entry in
/data/data/<package-name>. The folder are not readable and writable by an other user other than the owner of the app.
root user have access to any part of the system. Once the device is rooted, an app with root permissions can access any data on the system.
Rooting Android devices is discussed in the Rooting Android Devices