diff --git a/README.md b/README.md
index cdfa28c6..b9c44f55 100644
--- a/README.md
+++ b/README.md
@@ -41,6 +41,16 @@ Our app is designed to be easy to use and lightweight. Plus, it's free and open
 
 Download Android Studio Tutorials: Java Edition from the Google Play Store and begin your Android development journey today. It's free, easy to use, and perfect for beginners.
 
+## Architecture
+
+The app follows the modern layered architecture recommended by Google. The UI layer observes
+immutable state from ViewModels. Business logic is encapsulated in use case classes within the
+domain layer, which interact with repositories in the data layer. Each screen now exposes its
+operations through a small set of use cases. This pattern was inspired by the
+[Android Clean Architecture](https://github.com/android10/Android-CleanArchitecture) sample but
+implemented in a simplified form to avoid adding heavy dependencies. The result keeps the UI
+simple and ensures a clear separation of concerns across the whole app.
+
 ## Feedback
 
 We are constantly updating and improving Android Studio Tutorials: Java Edition to give you the best possible experience. If you have suggested features or improvements, please leave a review. If something isn't working correctly, let us know so we can fix it.
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/about/GetCurrentYearUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/about/GetCurrentYearUseCase.java
new file mode 100644
index 00000000..fbd94e0f
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/about/GetCurrentYearUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.about;
+
+import com.d4rk.androidtutorials.java.ui.screens.about.repository.AboutRepository;
+
+/** Provides current year as a string. */
+public class GetCurrentYearUseCase {
+    private final AboutRepository repository;
+
+    public GetCurrentYearUseCase(AboutRepository repository) {
+        this.repository = repository;
+    }
+
+    public String invoke() {
+        return repository.getCurrentYear();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/about/GetVersionStringUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/about/GetVersionStringUseCase.java
new file mode 100644
index 00000000..00839cda
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/about/GetVersionStringUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.about;
+
+import com.d4rk.androidtutorials.java.ui.screens.about.repository.AboutRepository;
+
+/** Returns the formatted app version string. */
+public class GetVersionStringUseCase {
+    private final AboutRepository repository;
+
+    public GetVersionStringUseCase(AboutRepository repository) {
+        this.repository = repository;
+    }
+
+    public String invoke() {
+        return repository.getVersionString();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/android/GetLessonUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/android/GetLessonUseCase.java
new file mode 100644
index 00000000..d8768c92
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/android/GetLessonUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.android;
+
+import com.d4rk.androidtutorials.java.ui.screens.android.repository.LessonRepository;
+
+/** Retrieves lesson data by name. */
+public class GetLessonUseCase {
+    private final LessonRepository repository;
+
+    public GetLessonUseCase(LessonRepository repository) {
+        this.repository = repository;
+    }
+
+    public LessonRepository.Lesson invoke(String lessonName) {
+        return repository.getLesson(lessonName);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/help/LaunchReviewFlowUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/help/LaunchReviewFlowUseCase.java
new file mode 100644
index 00000000..fd38e5e7
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/help/LaunchReviewFlowUseCase.java
@@ -0,0 +1,18 @@
+package com.d4rk.androidtutorials.java.domain.help;
+
+import android.app.Activity;
+import com.d4rk.androidtutorials.java.ui.screens.help.repository.HelpRepository;
+import com.google.android.play.core.review.ReviewInfo;
+
+/** Launches the in-app review flow. */
+public class LaunchReviewFlowUseCase {
+    private final HelpRepository repository;
+
+    public LaunchReviewFlowUseCase(HelpRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke(Activity activity, ReviewInfo info) {
+        repository.launchReviewFlow(activity, info);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/help/RequestReviewFlowUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/help/RequestReviewFlowUseCase.java
new file mode 100644
index 00000000..f5c4aada
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/help/RequestReviewFlowUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.help;
+
+import com.d4rk.androidtutorials.java.ui.screens.help.repository.HelpRepository;
+
+/** Requests the Google Play review flow. */
+public class RequestReviewFlowUseCase {
+    private final HelpRepository repository;
+
+    public RequestReviewFlowUseCase(HelpRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke(HelpRepository.OnReviewInfoListener listener) {
+        repository.requestReviewFlow(listener);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/home/GetDailyTipUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/home/GetDailyTipUseCase.java
new file mode 100644
index 00000000..b77e8f4a
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/home/GetDailyTipUseCase.java
@@ -0,0 +1,19 @@
+package com.d4rk.androidtutorials.java.domain.home;
+
+import com.d4rk.androidtutorials.java.ui.screens.home.repository.HomeRepository;
+
+/** Use case that provides the daily tip text. */
+public class GetDailyTipUseCase {
+    private final HomeRepository repository;
+
+    public GetDailyTipUseCase(HomeRepository repository) {
+        this.repository = repository;
+    }
+
+    /**
+     * Returns today's tip string.
+     */
+    public String invoke() {
+        return repository.getDailyTip();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/home/GetPromotedAppsUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/home/GetPromotedAppsUseCase.java
new file mode 100644
index 00000000..b48e781e
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/home/GetPromotedAppsUseCase.java
@@ -0,0 +1,26 @@
+package com.d4rk.androidtutorials.java.domain.home;
+
+import com.d4rk.androidtutorials.java.data.model.PromotedApp;
+import com.d4rk.androidtutorials.java.ui.screens.home.repository.HomeRepository;
+
+import java.util.List;
+
+/** Use case that fetches promoted apps from the repository. */
+public class GetPromotedAppsUseCase {
+    private final HomeRepository repository;
+
+    public interface Callback {
+        void onResult(List<PromotedApp> apps);
+    }
+
+    public GetPromotedAppsUseCase(HomeRepository repository) {
+        this.repository = repository;
+    }
+
+    /**
+     * Fetches the promoted apps and returns them via the callback.
+     */
+    public void invoke(Callback callback) {
+        repository.fetchPromotedApps(callback::onResult);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ApplyLanguageSettingsUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ApplyLanguageSettingsUseCase.java
new file mode 100644
index 00000000..0af07c4c
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ApplyLanguageSettingsUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+
+/** Applies the saved language preference. */
+public class ApplyLanguageSettingsUseCase {
+    private final MainRepository repository;
+
+    public ApplyLanguageSettingsUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke() {
+        repository.applyLanguageSettings();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ApplyThemeSettingsUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ApplyThemeSettingsUseCase.java
new file mode 100644
index 00000000..0fa78538
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ApplyThemeSettingsUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+
+/** Applies theme preference and returns true if changed. */
+public class ApplyThemeSettingsUseCase {
+    private final MainRepository repository;
+
+    public ApplyThemeSettingsUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public boolean invoke(String[] darkModeValues) {
+        return repository.applyThemeSettings(darkModeValues);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/BuildShortcutIntentUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/BuildShortcutIntentUseCase.java
new file mode 100644
index 00000000..be557a5e
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/BuildShortcutIntentUseCase.java
@@ -0,0 +1,17 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import android.content.Intent;
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+
+/** Creates an intent for the app shortcut. */
+public class BuildShortcutIntentUseCase {
+    private final MainRepository repository;
+
+    public BuildShortcutIntentUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public Intent invoke(boolean isInstalled) {
+        return repository.buildShortcutIntent(isInstalled);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetAppUpdateManagerUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetAppUpdateManagerUseCase.java
new file mode 100644
index 00000000..dec14c16
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetAppUpdateManagerUseCase.java
@@ -0,0 +1,17 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+import com.google.android.play.core.appupdate.AppUpdateManager;
+
+/** Provides the AppUpdateManager instance. */
+public class GetAppUpdateManagerUseCase {
+    private final MainRepository repository;
+
+    public GetAppUpdateManagerUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public AppUpdateManager invoke() {
+        return repository.getAppUpdateManager();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetBottomNavLabelVisibilityUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetBottomNavLabelVisibilityUseCase.java
new file mode 100644
index 00000000..121e2760
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetBottomNavLabelVisibilityUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+
+/** Returns bottom navigation label visibility preference. */
+public class GetBottomNavLabelVisibilityUseCase {
+    private final MainRepository repository;
+
+    public GetBottomNavLabelVisibilityUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public String invoke(String key, String defaultValue) {
+        return repository.getBottomNavLabelVisibility(key, defaultValue);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetDefaultTabPreferenceUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetDefaultTabPreferenceUseCase.java
new file mode 100644
index 00000000..37460727
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/GetDefaultTabPreferenceUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+
+/** Returns the default tab preference string. */
+public class GetDefaultTabPreferenceUseCase {
+    private final MainRepository repository;
+
+    public GetDefaultTabPreferenceUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public String invoke(String key, String defaultValue) {
+        return repository.getDefaultTabPreference(key, defaultValue);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/IsAppInstalledUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/IsAppInstalledUseCase.java
new file mode 100644
index 00000000..a1a2522a
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/IsAppInstalledUseCase.java
@@ -0,0 +1,17 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import android.content.pm.PackageManager;
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+
+/** Checks if an app is installed by package name. */
+public class IsAppInstalledUseCase {
+    private final MainRepository repository;
+
+    public IsAppInstalledUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public boolean invoke(PackageManager pm, String packageName) {
+        return repository.isAppInstalled(pm, packageName);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/MarkStartupScreenShownUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/MarkStartupScreenShownUseCase.java
new file mode 100644
index 00000000..cd6b0e2a
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/MarkStartupScreenShownUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+
+/** Marks that the startup screen has been shown. */
+public class MarkStartupScreenShownUseCase {
+    private final MainRepository repository;
+
+    public MarkStartupScreenShownUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke() {
+        repository.markStartupScreenShown();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ShouldShowStartupScreenUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ShouldShowStartupScreenUseCase.java
new file mode 100644
index 00000000..7967b28d
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/main/ShouldShowStartupScreenUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.main;
+
+import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+
+/** Determines if the startup screen should be shown. */
+public class ShouldShowStartupScreenUseCase {
+    private final MainRepository repository;
+
+    public ShouldShowStartupScreenUseCase(MainRepository repository) {
+        this.repository = repository;
+    }
+
+    public boolean invoke() {
+        return repository.shouldShowStartupScreen();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/quiz/LoadQuizQuestionsUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/quiz/LoadQuizQuestionsUseCase.java
new file mode 100644
index 00000000..fb92aa01
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/quiz/LoadQuizQuestionsUseCase.java
@@ -0,0 +1,18 @@
+package com.d4rk.androidtutorials.java.domain.quiz;
+
+import com.d4rk.androidtutorials.java.data.model.QuizQuestion;
+import com.d4rk.androidtutorials.java.ui.screens.quiz.repository.QuizRepository;
+import java.util.List;
+
+/** Loads quiz questions from assets. */
+public class LoadQuizQuestionsUseCase {
+    private final QuizRepository repository;
+
+    public LoadQuizQuestionsUseCase(QuizRepository repository) {
+        this.repository = repository;
+    }
+
+    public List<QuizQuestion> invoke() {
+        return repository.loadQuestions();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/ApplyConsentUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/ApplyConsentUseCase.java
new file mode 100644
index 00000000..12d23dbc
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/ApplyConsentUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.settings;
+
+import com.d4rk.androidtutorials.java.ui.screens.settings.repository.SettingsRepository;
+
+/** Applies the Firebase consent settings. */
+public class ApplyConsentUseCase {
+    private final SettingsRepository repository;
+
+    public ApplyConsentUseCase(SettingsRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke() {
+        repository.applyConsent();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/GetSharedPreferencesUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/GetSharedPreferencesUseCase.java
new file mode 100644
index 00000000..385167d5
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/GetSharedPreferencesUseCase.java
@@ -0,0 +1,17 @@
+package com.d4rk.androidtutorials.java.domain.settings;
+
+import android.content.SharedPreferences;
+import com.d4rk.androidtutorials.java.ui.screens.settings.repository.SettingsRepository;
+
+/** Provides shared preferences used by the settings screen. */
+public class GetSharedPreferencesUseCase {
+    private final SettingsRepository repository;
+
+    public GetSharedPreferencesUseCase(SettingsRepository repository) {
+        this.repository = repository;
+    }
+
+    public SharedPreferences invoke() {
+        return repository.getSharedPreferences();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/OnPreferenceChangedUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/OnPreferenceChangedUseCase.java
new file mode 100644
index 00000000..28473c08
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/settings/OnPreferenceChangedUseCase.java
@@ -0,0 +1,17 @@
+package com.d4rk.androidtutorials.java.domain.settings;
+
+import com.d4rk.androidtutorials.java.ui.screens.settings.repository.SettingsRepository;
+
+/** Handles a preference change and returns true if theme changed. */
+public class OnPreferenceChangedUseCase {
+    private final SettingsRepository repository;
+
+    public OnPreferenceChangedUseCase(SettingsRepository repository) {
+        this.repository = repository;
+    }
+
+    public boolean invoke(String key) {
+        repository.handlePreferenceChange(key);
+        return repository.applyTheme();
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/startup/LoadConsentFormUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/startup/LoadConsentFormUseCase.java
new file mode 100644
index 00000000..67e6376a
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/startup/LoadConsentFormUseCase.java
@@ -0,0 +1,17 @@
+package com.d4rk.androidtutorials.java.domain.startup;
+
+import android.app.Activity;
+import com.d4rk.androidtutorials.java.ui.screens.startup.repository.StartupRepository;
+
+/** Loads and shows the consent form if required. */
+public class LoadConsentFormUseCase {
+    private final StartupRepository repository;
+
+    public LoadConsentFormUseCase(StartupRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke(Activity activity, StartupRepository.OnFormError onError) {
+        repository.loadConsentForm(activity, onError);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/startup/RequestConsentInfoUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/startup/RequestConsentInfoUseCase.java
new file mode 100644
index 00000000..f5e4e06c
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/startup/RequestConsentInfoUseCase.java
@@ -0,0 +1,18 @@
+package com.d4rk.androidtutorials.java.domain.startup;
+
+import android.app.Activity;
+import com.d4rk.androidtutorials.java.ui.screens.startup.repository.StartupRepository;
+import com.google.android.ump.ConsentRequestParameters;
+
+/** Requests consent info update via UMP. */
+public class RequestConsentInfoUseCase {
+    private final StartupRepository repository;
+
+    public RequestConsentInfoUseCase(StartupRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke(Activity activity, ConsentRequestParameters params, Runnable onSuccess, StartupRepository.OnFormError onError) {
+        repository.requestConsentInfoUpdate(activity, params, onSuccess, onError);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitBillingClientUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitBillingClientUseCase.java
new file mode 100644
index 00000000..5a473bd5
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitBillingClientUseCase.java
@@ -0,0 +1,16 @@
+package com.d4rk.androidtutorials.java.domain.support;
+
+import com.d4rk.androidtutorials.java.ui.screens.support.repository.SupportRepository;
+
+/** Initializes billing client and invokes callback when connected. */
+public class InitBillingClientUseCase {
+    private final SupportRepository repository;
+
+    public InitBillingClientUseCase(SupportRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke(Runnable onConnected) {
+        repository.initBillingClient(onConnected);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitMobileAdsUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitMobileAdsUseCase.java
new file mode 100644
index 00000000..dd873a24
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitMobileAdsUseCase.java
@@ -0,0 +1,17 @@
+package com.d4rk.androidtutorials.java.domain.support;
+
+import com.d4rk.androidtutorials.java.databinding.ActivitySupportBinding;
+import com.d4rk.androidtutorials.java.ui.screens.support.repository.SupportRepository;
+
+/** Initializes Google Mobile Ads. */
+public class InitMobileAdsUseCase {
+    private final SupportRepository repository;
+
+    public InitMobileAdsUseCase(SupportRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke(ActivitySupportBinding binding) {
+        repository.initMobileAds(binding);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitiatePurchaseUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitiatePurchaseUseCase.java
new file mode 100644
index 00000000..1dcdf6aa
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/InitiatePurchaseUseCase.java
@@ -0,0 +1,17 @@
+package com.d4rk.androidtutorials.java.domain.support;
+
+import android.app.Activity;
+import com.d4rk.androidtutorials.java.ui.screens.support.repository.SupportRepository;
+
+/** Launches billing flow for a product. */
+public class InitiatePurchaseUseCase {
+    private final SupportRepository repository;
+
+    public InitiatePurchaseUseCase(SupportRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke(Activity activity, String productId) {
+        repository.initiatePurchase(activity, productId);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/QueryProductDetailsUseCase.java b/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/QueryProductDetailsUseCase.java
new file mode 100644
index 00000000..f0df70f8
--- /dev/null
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/domain/support/QueryProductDetailsUseCase.java
@@ -0,0 +1,18 @@
+package com.d4rk.androidtutorials.java.domain.support;
+
+import java.util.List;
+import com.d4rk.androidtutorials.java.ui.screens.support.repository.SupportRepository;
+
+/** Queries in-app product details. */
+public class QueryProductDetailsUseCase {
+    private final SupportRepository repository;
+
+    public QueryProductDetailsUseCase(SupportRepository repository) {
+        this.repository = repository;
+    }
+
+    public void invoke(List<String> productIds,
+                       SupportRepository.OnProductDetailsListener listener) {
+        repository.queryProductDetails(productIds, listener);
+    }
+}
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/about/AboutViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/about/AboutViewModel.java
index 0f8cdc67..89c7ce53 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/about/AboutViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/about/AboutViewModel.java
@@ -6,6 +6,8 @@
 import androidx.lifecycle.AndroidViewModel;
 
 import com.d4rk.androidtutorials.java.ui.screens.about.repository.AboutRepository;
+import com.d4rk.androidtutorials.java.domain.about.GetVersionStringUseCase;
+import com.d4rk.androidtutorials.java.domain.about.GetCurrentYearUseCase;
 
 
 /**
@@ -14,23 +16,27 @@
 public class AboutViewModel extends AndroidViewModel {
 
     private final AboutRepository repository;
+    private final GetVersionStringUseCase getVersionStringUseCase;
+    private final GetCurrentYearUseCase getCurrentYearUseCase;
 
     public AboutViewModel(@NonNull Application application) {
         super(application);
         repository = new AboutRepository(application);
+        getVersionStringUseCase = new GetVersionStringUseCase(repository);
+        getCurrentYearUseCase = new GetCurrentYearUseCase(repository);
     }
 
     /**
      * Returns a formatted version string, e.g. "v1.2.3 (45)".
      */
     public String getVersionString() {
-        return repository.getVersionString();
+        return getVersionStringUseCase.invoke();
     }
 
     /**
      * Returns the current year, e.g. "2024".
      */
     public String getCurrentYear() {
-        return repository.getCurrentYear();
+        return getCurrentYearUseCase.invoke();
     }
 }
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/android/CodeViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/android/CodeViewModel.java
index 1dfc78de..4842974c 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/android/CodeViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/android/CodeViewModel.java
@@ -5,13 +5,15 @@
 import androidx.lifecycle.ViewModel;
 
 import com.d4rk.androidtutorials.java.ui.screens.android.repository.LessonRepository;
+import com.d4rk.androidtutorials.java.domain.android.GetLessonUseCase;
 
 public class CodeViewModel extends ViewModel {
     private final MutableLiveData<LessonRepository.Lesson> lesson = new MutableLiveData<>();
     private final LessonRepository repository = new LessonRepository();
+    private final GetLessonUseCase getLessonUseCase = new GetLessonUseCase(repository);
 
     public void setLessonName(String lessonName) {
-        lesson.setValue(repository.getLesson(lessonName));
+        lesson.setValue(getLessonUseCase.invoke(lessonName));
     }
 
     public LiveData<LessonRepository.Lesson> getLesson() {
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/HelpActivity.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/HelpActivity.java
index 533d4be0..6ac4ac32 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/HelpActivity.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/HelpActivity.java
@@ -164,7 +164,7 @@ public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
                     if (requireActivity() instanceof HelpActivity helpActivity) {
                         HelpViewModel vm = helpActivity.getHelpViewModel();
 
-                        vm.requestReviewFlow(helpActivity, new HelpRepository.OnReviewInfoListener() {
+                        vm.requestReviewFlow(new HelpRepository.OnReviewInfoListener() {
                             @Override
                             public void onSuccess(ReviewInfo info) {
                                 vm.launchReviewFlow(helpActivity, info);
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/HelpViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/HelpViewModel.java
index f45488ca..c5b87950 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/HelpViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/HelpViewModel.java
@@ -8,6 +8,8 @@
 import androidx.lifecycle.AndroidViewModel;
 
 import com.d4rk.androidtutorials.java.ui.screens.help.repository.HelpRepository;
+import com.d4rk.androidtutorials.java.domain.help.RequestReviewFlowUseCase;
+import com.d4rk.androidtutorials.java.domain.help.LaunchReviewFlowUseCase;
 import com.google.android.play.core.review.ReviewInfo;
 
 /**
@@ -16,24 +18,28 @@
  */
 public class HelpViewModel extends AndroidViewModel {
 
+    private final RequestReviewFlowUseCase requestReviewFlowUseCase;
+    private final LaunchReviewFlowUseCase launchReviewFlowUseCase;
+
     public HelpViewModel(@NonNull Application application) {
         super(application);
+        HelpRepository repository = new HelpRepository(application);
+        requestReviewFlowUseCase = new RequestReviewFlowUseCase(repository);
+        launchReviewFlowUseCase = new LaunchReviewFlowUseCase(repository);
     }
 
     /**
      * Requests a review flow. On success, you get a ReviewInfo.
      * On failure, handle the exception (like fallback to the Play Store).
      */
-    public void requestReviewFlow(Activity activity, HelpRepository.OnReviewInfoListener listener) {
-        HelpRepository repository = new HelpRepository(activity);
-        repository.requestReviewFlow(listener);
+    public void requestReviewFlow(HelpRepository.OnReviewInfoListener listener) {
+        requestReviewFlowUseCase.invoke(listener);
     }
 
     /**
      * Launches the in-app review flow with the given ReviewInfo.
      */
     public void launchReviewFlow(Activity activity, ReviewInfo info) {
-        HelpRepository repository = new HelpRepository(activity);
-        repository.launchReviewFlow(activity, info);
+        launchReviewFlowUseCase.invoke(activity, info);
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/repository/HelpRepository.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/repository/HelpRepository.java
index ec597918..4f2361c7 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/repository/HelpRepository.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/help/repository/HelpRepository.java
@@ -1,6 +1,7 @@
 package com.d4rk.androidtutorials.java.ui.screens.help.repository;
 
 import android.app.Activity;
+import android.content.Context;
 
 import androidx.annotation.NonNull;
 
@@ -15,8 +16,8 @@ public class HelpRepository {
 
     private final ReviewManager reviewManager;
 
-    public HelpRepository(@NonNull Activity activity) {
-        this.reviewManager = ReviewManagerFactory.create(activity);
+    public HelpRepository(@NonNull Context context) {
+        this.reviewManager = ReviewManagerFactory.create(context);
     }
 
     /**
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/home/HomeViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/home/HomeViewModel.java
index 14a13487..99fa2f52 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/home/HomeViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/home/HomeViewModel.java
@@ -11,6 +11,8 @@
 import com.d4rk.androidtutorials.java.R;
 import com.d4rk.androidtutorials.java.data.model.PromotedApp;
 import com.d4rk.androidtutorials.java.ui.screens.home.repository.HomeRepository;
+import com.d4rk.androidtutorials.java.domain.home.GetDailyTipUseCase;
+import com.d4rk.androidtutorials.java.domain.home.GetPromotedAppsUseCase;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -19,6 +21,8 @@
 public class HomeViewModel extends AndroidViewModel {
 
     private final HomeRepository homeRepository;
+    private final GetDailyTipUseCase getDailyTipUseCase;
+    private final GetPromotedAppsUseCase getPromotedAppsUseCase;
 
     private final MutableLiveData<String> announcementTitle = new MutableLiveData<>();
     private final MutableLiveData<String> announcementSubtitle = new MutableLiveData<>();
@@ -28,12 +32,14 @@ public class HomeViewModel extends AndroidViewModel {
     public HomeViewModel(@NonNull Application application) {
         super(application);
         homeRepository = new HomeRepository(application);
+        getDailyTipUseCase = new GetDailyTipUseCase(homeRepository);
+        getPromotedAppsUseCase = new GetPromotedAppsUseCase(homeRepository);
 
         announcementTitle.setValue(application.getString(R.string.announcement_title));
         announcementSubtitle.setValue(application.getString(R.string.announcement_subtitle));
-        dailyTip.setValue(homeRepository.getDailyTip());
+        dailyTip.setValue(getDailyTipUseCase.invoke());
 
-        homeRepository.fetchPromotedApps(apps -> {
+        getPromotedAppsUseCase.invoke(apps -> {
             if (apps.isEmpty()) {
                 promotedApps.postValue(apps);
                 return;
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/main/MainViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/main/MainViewModel.java
index 3f1cda99..bb9c5a88 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/main/MainViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/main/MainViewModel.java
@@ -11,6 +11,15 @@
 
 import com.d4rk.androidtutorials.java.R;
 import com.d4rk.androidtutorials.java.ui.screens.main.repository.MainRepository;
+import com.d4rk.androidtutorials.java.domain.main.ApplyThemeSettingsUseCase;
+import com.d4rk.androidtutorials.java.domain.main.GetBottomNavLabelVisibilityUseCase;
+import com.d4rk.androidtutorials.java.domain.main.GetDefaultTabPreferenceUseCase;
+import com.d4rk.androidtutorials.java.domain.main.ApplyLanguageSettingsUseCase;
+import com.d4rk.androidtutorials.java.domain.main.ShouldShowStartupScreenUseCase;
+import com.d4rk.androidtutorials.java.domain.main.MarkStartupScreenShownUseCase;
+import com.d4rk.androidtutorials.java.domain.main.IsAppInstalledUseCase;
+import com.d4rk.androidtutorials.java.domain.main.BuildShortcutIntentUseCase;
+import com.d4rk.androidtutorials.java.domain.main.GetAppUpdateManagerUseCase;
 import com.google.android.material.navigation.NavigationBarView;
 import com.google.android.play.core.appupdate.AppUpdateManager;
 
@@ -21,6 +30,15 @@
 public class MainViewModel extends AndroidViewModel {
 
     private final MainRepository mainRepository;
+    private final ApplyThemeSettingsUseCase applyThemeSettingsUseCase;
+    private final GetBottomNavLabelVisibilityUseCase getBottomNavLabelVisibilityUseCase;
+    private final GetDefaultTabPreferenceUseCase getDefaultTabPreferenceUseCase;
+    private final ApplyLanguageSettingsUseCase applyLanguageSettingsUseCase;
+    private final ShouldShowStartupScreenUseCase shouldShowStartupScreenUseCase;
+    private final MarkStartupScreenShownUseCase markStartupScreenShownUseCase;
+    private final IsAppInstalledUseCase isAppInstalledUseCase;
+    private final BuildShortcutIntentUseCase buildShortcutIntentUseCase;
+    private final GetAppUpdateManagerUseCase getAppUpdateManagerUseCase;
     private final MutableLiveData<Integer> bottomNavLabelVisibility = new MutableLiveData<>();
     private final MutableLiveData<Integer> defaultNavDestination = new MutableLiveData<>();
     private final MutableLiveData<Boolean> themeChanged = new MutableLiveData<>();
@@ -28,6 +46,15 @@ public class MainViewModel extends AndroidViewModel {
     public MainViewModel(@NonNull Application application) {
         super(application);
         mainRepository = new MainRepository(application);
+        applyThemeSettingsUseCase = new ApplyThemeSettingsUseCase(mainRepository);
+        getBottomNavLabelVisibilityUseCase = new GetBottomNavLabelVisibilityUseCase(mainRepository);
+        getDefaultTabPreferenceUseCase = new GetDefaultTabPreferenceUseCase(mainRepository);
+        applyLanguageSettingsUseCase = new ApplyLanguageSettingsUseCase(mainRepository);
+        shouldShowStartupScreenUseCase = new ShouldShowStartupScreenUseCase(mainRepository);
+        markStartupScreenShownUseCase = new MarkStartupScreenShownUseCase(mainRepository);
+        isAppInstalledUseCase = new IsAppInstalledUseCase(mainRepository);
+        buildShortcutIntentUseCase = new BuildShortcutIntentUseCase(mainRepository);
+        getAppUpdateManagerUseCase = new GetAppUpdateManagerUseCase(mainRepository);
     }
 
     private static int getVisibilityMode(String labelVisibilityStr, String[] bottomNavBarLabelsValues) {
@@ -47,7 +74,7 @@ private static int getVisibilityMode(String labelVisibilityStr, String[] bottomN
      * This can be called from onCreate() or similar lifecycle methods in MainActivity.
      */
     public void applySettings() {
-        boolean changedTheme = mainRepository.applyThemeSettings(
+        boolean changedTheme = applyThemeSettingsUseCase.invoke(
                 getApplication().getResources().getStringArray(R.array.preference_theme_values)
         );
         themeChanged.setValue(changedTheme);
@@ -57,7 +84,7 @@ public void applySettings() {
         String[] bottomNavBarLabelsValues =
                 getApplication().getResources().getStringArray(R.array.preference_bottom_navigation_bar_labels_values);
 
-        String labelVisibilityStr = mainRepository.getBottomNavLabelVisibility(labelKey, labelDefaultValue);
+        String labelVisibilityStr = getBottomNavLabelVisibilityUseCase.invoke(labelKey, labelDefaultValue);
         int visibilityMode = getVisibilityMode(labelVisibilityStr, bottomNavBarLabelsValues);
         bottomNavLabelVisibility.setValue(visibilityMode);
 
@@ -65,7 +92,7 @@ public void applySettings() {
         String defaultTabValue = getApplication().getString(R.string.default_value_tab);
         String[] defaultTabValues = getApplication().getResources().getStringArray(R.array.preference_default_tab_values);
 
-        String startFragmentIdValue = mainRepository.getDefaultTabPreference(defaultTabKey, defaultTabValue);
+        String startFragmentIdValue = getDefaultTabPreferenceUseCase.invoke(defaultTabKey, defaultTabValue);
         int startFragmentId;
         if (startFragmentIdValue.equals(defaultTabValues[0])) {
             startFragmentId = R.id.navigation_home;
@@ -77,21 +104,21 @@ public void applySettings() {
             startFragmentId = R.id.navigation_home;
         }
         defaultNavDestination.setValue(startFragmentId);
-        mainRepository.applyLanguageSettings();
+        applyLanguageSettingsUseCase.invoke();
     }
 
     /**
      * Checks if we need to show the startup screen.
      */
     public boolean shouldShowStartupScreen() {
-        return mainRepository.shouldShowStartupScreen();
+        return shouldShowStartupScreenUseCase.invoke();
     }
 
     /**
      * Mark startup screen as shown.
      */
     public void markStartupScreenShown() {
-        mainRepository.markStartupScreenShown();
+        markStartupScreenShownUseCase.invoke();
     }
 
     /**
@@ -99,14 +126,14 @@ public void markStartupScreenShown() {
      */
     public boolean isAndroidTutorialsInstalled() {
         PackageManager pm = getApplication().getPackageManager();
-        return mainRepository.isAppInstalled(pm, "com.d4rk.androidtutorials.java");
+        return isAppInstalledUseCase.invoke(pm, "com.d4rk.androidtutorials.java");
     }
 
     /**
      * Build the intent for the shortcut (opens app if installed, or fallback to the Play Store).
      */
     public Intent getShortcutIntent(boolean isInstalled) {
-        return mainRepository.buildShortcutIntent(isInstalled);
+        return buildShortcutIntentUseCase.invoke(isInstalled);
     }
 
     /**
@@ -134,6 +161,6 @@ public LiveData<Boolean> getThemeChanged() {
      * Expose the AppUpdateManager if the Activity wants to directly check for in-app updates.
      */
     public AppUpdateManager getAppUpdateManager() {
-        return mainRepository.getAppUpdateManager();
+        return getAppUpdateManagerUseCase.invoke();
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/quiz/QuizViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/quiz/QuizViewModel.java
index 84f52f46..c24bebf6 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/quiz/QuizViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/quiz/QuizViewModel.java
@@ -9,6 +9,7 @@
 
 import com.d4rk.androidtutorials.java.data.model.QuizQuestion;
 import com.d4rk.androidtutorials.java.ui.screens.quiz.repository.QuizRepository;
+import com.d4rk.androidtutorials.java.domain.quiz.LoadQuizQuestionsUseCase;
 
 import java.util.List;
 
@@ -20,11 +21,13 @@ public class QuizViewModel extends AndroidViewModel {
     private final List<QuizQuestion> questions;
     private final MutableLiveData<Integer> currentIndex = new MutableLiveData<>(0);
     private final MutableLiveData<Integer> score = new MutableLiveData<>(0);
+    private final LoadQuizQuestionsUseCase loadQuizQuestionsUseCase;
 
     public QuizViewModel(@NonNull Application application) {
         super(application);
         QuizRepository repository = new QuizRepository(application);
-        questions = repository.loadQuestions();
+        loadQuizQuestionsUseCase = new LoadQuizQuestionsUseCase(repository);
+        questions = loadQuizQuestionsUseCase.invoke();
     }
 
     public QuizQuestion getCurrentQuestion() {
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/settings/SettingsViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/settings/SettingsViewModel.java
index 490c319b..e7f1dcbe 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/settings/SettingsViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/settings/SettingsViewModel.java
@@ -7,6 +7,9 @@
 import androidx.lifecycle.AndroidViewModel;
 
 import com.d4rk.androidtutorials.java.ui.screens.settings.repository.SettingsRepository;
+import com.d4rk.androidtutorials.java.domain.settings.OnPreferenceChangedUseCase;
+import com.d4rk.androidtutorials.java.domain.settings.GetSharedPreferencesUseCase;
+import com.d4rk.androidtutorials.java.domain.settings.ApplyConsentUseCase;
 
 
 /**
@@ -16,10 +19,16 @@
 public class SettingsViewModel extends AndroidViewModel {
 
     private final SettingsRepository settingsRepository;
+    private final OnPreferenceChangedUseCase onPreferenceChangedUseCase;
+    private final GetSharedPreferencesUseCase getSharedPreferencesUseCase;
+    private final ApplyConsentUseCase applyConsentUseCase;
 
     public SettingsViewModel(@NonNull Application application) {
         super(application);
         settingsRepository = new SettingsRepository(application);
+        onPreferenceChangedUseCase = new OnPreferenceChangedUseCase(settingsRepository);
+        getSharedPreferencesUseCase = new GetSharedPreferencesUseCase(settingsRepository);
+        applyConsentUseCase = new ApplyConsentUseCase(settingsRepository);
     }
 
     /**
@@ -28,15 +37,14 @@ public SettingsViewModel(@NonNull Application application) {
      */
     public boolean onPreferenceChanged(String key) {
         if (key == null) return false;
-        settingsRepository.handlePreferenceChange(key);
-        return settingsRepository.applyTheme();
+        return onPreferenceChangedUseCase.invoke(key);
     }
 
     public SharedPreferences getSharedPreferences() {
-        return settingsRepository.getSharedPreferences();
+        return getSharedPreferencesUseCase.invoke();
     }
 
     public void applyConsent() {
-        settingsRepository.applyConsent();
+        applyConsentUseCase.invoke();
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/startup/StartupViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/startup/StartupViewModel.java
index 8d14f604..4d2a5250 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/startup/StartupViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/startup/StartupViewModel.java
@@ -8,6 +8,8 @@
 import androidx.lifecycle.AndroidViewModel;
 
 import com.d4rk.androidtutorials.java.ui.screens.startup.repository.StartupRepository;
+import com.d4rk.androidtutorials.java.domain.startup.RequestConsentInfoUseCase;
+import com.d4rk.androidtutorials.java.domain.startup.LoadConsentFormUseCase;
 import com.google.android.ump.ConsentRequestParameters;
 
 /**
@@ -16,8 +18,14 @@
  */
 public class StartupViewModel extends AndroidViewModel {
 
+    private final RequestConsentInfoUseCase requestConsentInfoUseCase;
+    private final LoadConsentFormUseCase loadConsentFormUseCase;
+
     public StartupViewModel(@NonNull Application application) {
         super(application);
+        StartupRepository repository = new StartupRepository(application);
+        requestConsentInfoUseCase = new RequestConsentInfoUseCase(repository);
+        loadConsentFormUseCase = new LoadConsentFormUseCase(repository);
     }
 
     /**
@@ -27,20 +35,13 @@ public void requestConsentInfoUpdate(Activity activity,
                                          ConsentRequestParameters params,
                                          Runnable onSuccess,
                                          StartupRepository.OnFormError onError) {
-        StartupRepository localRepo = new StartupRepository(activity);
-        localRepo.requestConsentInfoUpdate(
-                activity,
-                params,
-                onSuccess,
-                onError
-        );
+        requestConsentInfoUseCase.invoke(activity, params, onSuccess, onError);
     }
 
     /**
      * Load the consent form (and show it if required).
      */
     public void loadConsentForm(Activity activity, StartupRepository.OnFormError onError) {
-        StartupRepository localRepo = new StartupRepository(activity);
-        localRepo.loadConsentForm(activity, onError);
+        loadConsentFormUseCase.invoke(activity, onError);
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/startup/repository/StartupRepository.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/startup/repository/StartupRepository.java
index c675e88d..6ee4e198 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/startup/repository/StartupRepository.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/startup/repository/StartupRepository.java
@@ -1,6 +1,7 @@
 package com.d4rk.androidtutorials.java.ui.screens.startup.repository;
 
 import android.app.Activity;
+import android.content.Context;
 
 import com.google.android.ump.ConsentForm;
 import com.google.android.ump.ConsentInformation;
@@ -17,8 +18,8 @@ public class StartupRepository {
     private final ConsentInformation consentInformation;
     private ConsentForm consentForm;
 
-    public StartupRepository(Activity activity) {
-        consentInformation = UserMessagingPlatform.getConsentInformation(activity);
+    public StartupRepository(Context context) {
+        consentInformation = UserMessagingPlatform.getConsentInformation(context);
     }
 
     /**
diff --git a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/support/SupportViewModel.java b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/support/SupportViewModel.java
index d70fa4c2..aacb00a6 100644
--- a/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/support/SupportViewModel.java
+++ b/app/src/main/java/com/d4rk/androidtutorials/java/ui/screens/support/SupportViewModel.java
@@ -8,32 +8,44 @@
 
 import com.d4rk.androidtutorials.java.databinding.ActivitySupportBinding;
 import com.d4rk.androidtutorials.java.ui.screens.support.repository.SupportRepository;
+import com.d4rk.androidtutorials.java.domain.support.InitBillingClientUseCase;
+import com.d4rk.androidtutorials.java.domain.support.QueryProductDetailsUseCase;
+import com.d4rk.androidtutorials.java.domain.support.InitiatePurchaseUseCase;
+import com.d4rk.androidtutorials.java.domain.support.InitMobileAdsUseCase;
 
 import java.util.List;
 
 public class SupportViewModel extends AndroidViewModel {
 
     private final SupportRepository repository;
+    private final InitBillingClientUseCase initBillingClientUseCase;
+    private final QueryProductDetailsUseCase queryProductDetailsUseCase;
+    private final InitiatePurchaseUseCase initiatePurchaseUseCase;
+    private final InitMobileAdsUseCase initMobileAdsUseCase;
 
     public SupportViewModel(@NonNull Application application) {
         super(application);
         repository = new SupportRepository(application);
+        initBillingClientUseCase = new InitBillingClientUseCase(repository);
+        queryProductDetailsUseCase = new QueryProductDetailsUseCase(repository);
+        initiatePurchaseUseCase = new InitiatePurchaseUseCase(repository);
+        initMobileAdsUseCase = new InitMobileAdsUseCase(repository);
     }
 
     public void initBillingClient(Runnable onConnected) {
-        repository.initBillingClient(onConnected);
+        initBillingClientUseCase.invoke(onConnected);
     }
 
     public void queryProductDetails(List<String> productIds,
                                    SupportRepository.OnProductDetailsListener listener) {
-        repository.queryProductDetails(productIds, listener);
+        queryProductDetailsUseCase.invoke(productIds, listener);
     }
 
     public void initiatePurchase(Activity activity, String productId) {
-        repository.initiatePurchase(activity, productId);
+        initiatePurchaseUseCase.invoke(activity, productId);
     }
 
     public void initMobileAds(ActivitySupportBinding binding) {
-        repository.initMobileAds(binding);
+        initMobileAdsUseCase.invoke(binding);
     }
 }
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