An app whose package name is com.example.app
has its data files in /data/data/com.example.app
. This applies to pre–Jelly Bean systems, and to the first user on Jelly Bean systems. For other users on Jelly Bean systems, user 1 has the data files for com.example.app
in /data/user/1/com.example.app
, and so on.
Reading another app's data files can only be done on a rooted phone. Even then, you need an app that's designed to work with root access. See the rooting tag wiki, and How do I root my Android device? for more info, but bear in mind that rooting will void your warranty.