As mentioned by the other answerers, any app which wishes to access the internet, must declare the android.permission.INTERNET undeniable permission within its AndroidManifest.xml. How does Android remember which permissions an app requested, though? By saving them inside packages.xml, a protected file located at /data/system.
You can test your app with the permission enforced by either running your app on the Android Emulator when running Android 4.1 or higher, or enabling Protect USB storage under Developer options in the Settings app on a device running Android 4.1 or higher. 12 Most Abused Android App Permissions - Trend Micro Android apps need permissions in order to work. However, cybercriminals can exploit them for their personal gain. PermissionsAndroid · React Native PermissionsAndroid provides access to Android M's new permissions model. The so-called "normal" permissions are granted by default when the application is installed as long as they appear in AndroidManifest.xml.However, "dangerous" permissions require a dialog prompt. Android Easy Runtime Permissions with Dexter Dec 31, 2017
Android apps need permissions in order to work. However, cybercriminals can exploit them for their personal gain.
Jul 19, 2018 Show no Internet connection Dialog in Android – AndroidMkab
Change permissions for apps on your Android phone
Add uses-permission of "android.permission.INTERNET" to Mar 29, 2016