Removed interface AppConfig, since it is technically not needed.

src/main/java/de/dennisguse/opentracks/AppConfig.java

@@ -1,10 +0,0 @@
-package de.dennisguse.opentracks;
-
-public interface AppConfig {
-    /**
-     * Returns the name of the database used by SQLiteOpenHelper.
-     * See {@link android.database.sqlite.SQLiteOpenHelper} for details.
-     * @return SQLite database name.
-     */
-    String getDatabaseName();
-}

src/main/java/de/dennisguse/opentracks/Startup.java

@@ -14,7 +14,7 @@ import de.dennisguse.opentracks.settings.PreferencesUtils;
  * NOTE: How often actual application startup happens depends on the OS.
  * Not every start of an activity will trigger this.
  */
-public class Startup extends Application implements AppConfig {
+public class Startup extends Application {
 
     private static final String TAG = Startup.class.getSimpleName();
 
@@ -41,7 +41,11 @@ public class Startup extends Application implements AppConfig {
         }
     }
 
-    @Override
+    /**
+     * Returns the name of the database used by SQLiteOpenHelper.
+     * See {@link android.database.sqlite.SQLiteOpenHelper} for details.
+     * @return SQLite database name.
+     */
     public String getDatabaseName() {
         return "database.db";
     }

src/main/java/de/dennisguse/opentracks/content/provider/CustomSQLiteOpenHelper.java

@@ -11,7 +11,7 @@ import androidx.annotation.VisibleForTesting;
 
 import java.util.UUID;
 
-import de.dennisguse.opentracks.AppConfig;
+import de.dennisguse.opentracks.Startup;
 import de.dennisguse.opentracks.content.data.MarkerColumns;
 import de.dennisguse.opentracks.content.data.Track;
 import de.dennisguse.opentracks.content.data.TrackPointsColumns;
@@ -29,7 +29,7 @@ public class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
     private static final int DATABASE_VERSION = 31;
 
     public CustomSQLiteOpenHelper(Context context) {
-        this(context, ((AppConfig) context.getApplicationContext()).getDatabaseName());
+        this(context, ((Startup) context.getApplicationContext()).getDatabaseName());
     }
 
     @VisibleForTesting