'checkDebugDuplicateClasses' how to fix this issue

Question

While merging two projects in Android Studio I got this problem.
Duplicate class android.support.v4.app.INotificationSideChannel found in modules core-1.9.0-runtime (androidx.core:core:1.9.0) and support-compat-27.1.1-runtime (com.android.support:support-compat:27.1.1)
I have searched it in the internet ? there was said to fix it it's anougth to add 2 lines code "android.useAndroidX=true
android.enableJetifier=true"
but whenI added "android.enableJetifier=true" <- this line I got a lot of errors. Help me , please ,I will
appreciate any hepl.

I need to connect in Android Studio to one project. there are 2 andre applications (ready-made). It is necessary to make one project out of them. When the user launches the application, the main interface should open. and it should have 2 buttons. you need to make it so that the user sees one of the two buttons, can select one of the two applications.

Answer 1

I don't know too much in android but read the error carefully 'checkDebugDuplicateClasses' it means you have made 2 duplicate classes, please check again