I've seen that many solutions to this problem either you have to root your phone or you have to install an app. Then after much googling I got this solution for non rooted/rooted phones.
To list which apps you got so far.
adb shell pm list packages
Then you may select an app, for instance twitter
adb backup -apk com.twitter.android
An important thing here is to not set up a password for encrypt your backup
This is going to create a file named as backup.ap, but you still can't open it. For this you got to extract it again but using the dd command.
dd if=backup.ab bs=24 skip=1 | openssl zlib -d > backup.tar
After this all you have to do is to extract the tar content and it's done.
Hope it works for you guys