Account Authenticator is a Account Manager created with Google Accounts, AccountManager library.

With this all the user acc can be stored in system and the information can be retained even after log out. Here also token and auth token implemented. Where user will be logged in based on session auth.

Features,

1. Add account to the AccountManager with AUTHENTICATE_ACCOUNTS
2. Account exist or not checking
3. Get password from account manager.
4. Password, Toker and Username validator
5. Get an Auth Token from the AccountManager's cache for a given Account type
6. Add an auth token to the AccountManager cache for an account.
7. Invalidate an auth token to the AccountManager cache for an account.

Reference

Google AccountManager: https://developer.android.com/reference/android/accounts/AccountManager