Class not found exception on firebase messaging flutter

Question

I keep getting classNotFoundException when sending cloud notifications from firebase. The error logs that it can not find .java.MyFirebaseMessagingService I have followed everything as per the documentation but still can not find the fix. Here's the error log. The app opens fine and only crashes when I send a message from the firebase console to test.

java.lang.RuntimeException: Unable to instantiate service com.myapp.MyApp.MyFirebaseMessagingService: java.lang.ClassNotFoundException: Didn't find class "com.myapp.MyApp.MyFirebaseMessagingService" on path: DexPathList[[zip file "/data/app/com.myapp.MyApp-2_H2R81paYjm5b8ZDse8Uw==/base.apk"],nativeLibraryDirectories=[/data/app/com.myapp.MyApp-2_H2R81paYjm5b8ZDse8Uw==/lib/arm64, /data/app/com.myapp.MyApp-2_H2R81paYjm5b8ZDse8Uw==/base.apk!/lib/arm64-v8a, /system/lib64, /vendor/lib64]]
E/AndroidRuntime( 5956):    at android.app.ActivityThread.handleCreateService(ActivityThread.java:3577)
E/AndroidRuntime( 5956):    at android.app.ActivityThread.-wrap4(Unknown Source:0)
E/AndroidRuntime( 5956):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1862)
E/AndroidRuntime( 5956):    at android.os.Handler.dispatchMessage(Handler.java:106)
E/AndroidRuntime( 5956):    at android.os.Looper.loop(Looper.java:198)
E/AndroidRuntime( 5956):    at android.app.ActivityThread.main(ActivityThread.java:7055)
E/AndroidRuntime( 5956):    at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime( 5956):    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:523)
E/AndroidRuntime( 5956):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:836)
E/AndroidRuntime( 5956): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.myapp.MyAppMyFirebaseMessagingService" on path: DexPathList[[zip file "/data/app/com.myapp.MyApp-2_H2R81paYjm5b8ZDse8Uw==/base.apk"],nativeLibraryDirectories=[/data/app/com.myapp.MyApp-2_H2R81paYjm5b8ZDse8Uw==/lib/arm64, /data/app/com.myapp.MyApp-2_H2R81paYjm5b8ZDse8Uw==/base.apk!/lib/arm64-v8a, /system/lib64, /vendor/lib64]]
E/AndroidRuntime( 5956):    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:125)
E/AndroidRuntime( 5956):    at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
E/AndroidRuntime( 5956):    at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
E/AndroidRuntime( 5956):    at android.app.ActivityThread.handleCreateService(ActivityThread.java:3574)
E/AndroidRuntime( 5956):    ... 8 more

And the manifest file is.

<application
        android:name=".Application"
        android:label="MyApp"
        android:icon="@mipmap/ic_launcher">

        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:showWhenLocked="true"
            android:turnScreenOn="true"
            android:windowSoftInputMode="adjustResize">
            <!-- Specifies an Android theme to apply to this Activity as soon as
                 the Android process has started. This theme is visible to the user
                 while the Flutter UI initializes. After that, this theme continues
                 to determine the Window background behind the Flutter UI. -->
            <meta-data
              android:name="io.flutter.embedding.android.NormalTheme"
              android:resource="@style/NormalTheme"
              />
            <!-- Displays an Android View that continues showing the launch screen
                 Drawable until Flutter paints its first frame, then this splash
                 screen fades out. A splash screen is useful to avoid any visual
                 gap between the end of Android's launch screen and the painting of
                 Flutter's first frame. -->
            <meta-data
              android:name="io.flutter.embedding.android.SplashScreenDrawable"
              android:resource="@drawable/launch_background"
              />

            <meta-data
                    android:name="com.google.firebase.messaging.default_notification_icon"
                    android:resource="@mipmap/ic_logo" />

            <meta-data
                    android:name="com.google.firebase.messaging.default_notification_color"
                    android:resource="@color/colorAccent" />
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            
                <action android:name="FLUTTER_NOTIFICATION_CLICK" />
                <category android:name="android.intent.category.DEFAULT" />


            </intent-filter>
        </activity>

        <service
                android:name=".service.MyFirebaseMessagingService"
                >
            <intent-filter>
                <action android:name="com.google.firebase.MESSAGING_EVENT" />
            </intent-filter>
        </service>
        <!-- Don't delete the meta-data below.
             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
    </application>

Answer 1

I know that the question is answered but recently I too got stuck in the same issue and your comment saved me. Thanks! I want to increase the visibility of your answer for others.
To resolve this issue. I just removed this code segment and the application started working as intended:

<service
        android:name=".service.MyFirebaseMessagingService"
        >
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT" />
    </intent-filter>
</service>

I think there is no need to explicitly declare class .service.MyFirebaseMessagingService as you don't need to mention it for the projects.

---

Follow all the instructions provided in the firebase_messaging | Flutter Package.

You may get one error error: incompatible types: PluginRegistry cannot be converted to FlutterEngine GeneratedPluginRegistrant.register with (registry); while following the instruction. To solve this error, follow the instructions provided in this thread: PluginRegistry cannot be converted to FlutterEngine and you won't face any issues.

Answer 2

If you want to listen for messages on Background / Foreground , You don't need :

<service android:name=".service.MyFirebaseMessagingService">

The Flutter Package gives to you other tools to make this happen.

If you want to use Flutter for listening to Firebase PushNotifications (and not the native way), try to use the FirebaseMessaging.onMessage.listen( ... ) dart function.

And remember, for android:

If the application is currently in the foreground, the visible notification is not presented by default (but you can make it happen).

You can check how to use the notification handling in the Firebase flutter documentation:

https://firebase.flutter.dev/docs/messaging/notifications/

✌️

Answer 3

At the time of writing I am using flutter firebase_messaging package v14.2.3.

I have opened the project in Android Studio and looked for the FlutterFirebaseMessagingService class in imported packages.

The fix that worked for me was using this class name io.flutter.plugins.firebase.messaging.FlutterFirebaseMessagingService in android/app/src/main/AndroidManifest.xml:

        <service
            android:name="io.flutter.plugins.firebase.messaging.FlutterFirebaseMessagingService"
            android:exported="false">
            <intent-filter>
                <action android:name="com.google.firebase.MESSAGING_EVENT" />
            </intent-filter>
        </service>