Interface is terrible! You should never use interfaces to inter-activity comunnication

[SelvinPL]

In the example you are using AcquireTokenFragment it has acquireTokenCallback which is passed MsalWrapper which wrapps it with AuthenticationCallback

This is very bad code practice in android development - you are leaking fragment which MAY BE DEAD after code from this library (MAY AND WILL BE DEAD - if you enable "Don't keep activities" - and callback will be called on not atached dead fragment/activity)

Proper flow should be using Activity/Fragment.startActivityForResult/registerForActivityResult for IPublicClientApplication.acquireToken and ISingleAccountPublicClientApplication.signIn (and other functions which starts new activity)

It is ok for acquireTokenSilent to use callback since it doesn't start new activity