this should be the correct syntax of the application class package YOUR.PACKAGE.NAME; import io.flutter.app.FlutterApplication; import io.flutter.plugin.common.PluginRegistry; import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback; import io.flutter.plugins.GeneratedPluginRegistrant; import io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService; import io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin;//<-- the correct import here import io.flutter.embedding.engine.FlutterEngine; public class Application extends FlutterApplication implements PluginRegistrantCallback { @Override public void onCreate() { super.onCreate(); FlutterFirebaseMessagingService.setPluginRegistrant(this); } @Override public void registerWith(PluginRegistry registry) { FirebaseMessagingPlugin.registerWith(registry.registrarFor("io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin")); } }