Fatal Exception: java.lang.LinkageError

Firebase crash analytics is reporting the following error on android devices

Fatal Exception: java.lang.LinkageError: Method java.lang.Object com.google.android.gms.internal.ads.jo3.zzb() overrides final method in class Lcom/google/android/gms/internal/ads/bo3; (declaration of 'com.google.android.gms.internal.ads.jo3' appears in base.apk)
       at com.google.android.gms.internal.ads.zzcpr.<init>(zzcpr.java:310)
       at com.google.android.gms.internal.ads.zzcpq.zza(zzcpq.java:103)
       at com.google.android.gms.internal.ads.zzevk.zza(zzevk.java:365)
       at com.google.android.gms.internal.ads.zzeke.zzN(zzeke.java:58)
       at com.google.android.gms.internal.ads.zzeke.zze(zzeke.java:6)
       at com.google.android.gms.internal.ads.zzbhd.zzg(zzbhd.java:203)
       at com.google.android.gms.ads.BaseAdView.loadAd(BaseAdView.java:6)
       at io.flutter.plugins.googlemobileads.FlutterBannerAd.load(FlutterBannerAd.java:60)
       at io.flutter.plugins.googlemobileads.GoogleMobileAdsPlugin.onMethodCall(GoogleMobileAdsPlugin.java:737)
       at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:17)
       at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:18)
       at io.flutter.embedding.engine.dart.DartMessenger.lambda$handleMessageFromDart$0(DartMessenger.java:20)
       at io.flutter.embedding.engine.dart.DartMessenger.lambda$handleMessageFromDart$0$DartMessenger(DartMessenger.java)
       at io.flutter.embedding.engine.dart.-$$Lambda$DartMessenger$6ZD1MYkhaLxyPjtoFDxe45u43DI.run(-.java:12)
       at android.os.Handler.handleCallback(Handler.java:938)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:246)
       at android.app.ActivityThread.main(ActivityThread.java:8550)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)

This is the line it errors on

at io.flutter.plugins.googlemobileads.FlutterBannerAd.load(FlutterBannerAd.java:60)

on the following devices

Im am using google_mobile_ads google_mobile_ads: ^1.0.1

and Flutter 2.8.0

Edit:

This is our statefull widget

class MyBannerAd extends StatefulWidget {
  const MyBannerAd();

  @override
  _MyBannerAdState createState() => _MyBannerAdState();
}

class _MyBannerAdState extends State<MyBannerAd> {
  late AdSize adSize;
  late AdMobRepository adRepository;
  late AnalyticsRepository analyticsRepository;
  bool adLoaded = false;
  BannerAd? anchoredBanner;

  @override
  void initState() {
    super.initState();
    adRepository = context.read<AdMobRepository>();
    analyticsRepository = context.read<AnalyticsRepository>();

    if (SizerUtil.deviceType != DeviceType.mobile && SizerUtil.orientation == Orientation.portrait) {
      adSize = AdSize.leaderboard;
    } else {
      adSize = AdSize.largeBanner;
    }

    final bannerAd = adRepository.getBannerAd(
      size: adSize,
      onFailedLoad: (ad, error) {
        print('banner ad failed to load: $error');
        ad.dispose();
      },
      onLoad: (ad) {
        setState(() {
          adLoaded = true;
          anchoredBanner = ad as BannerAd?;
        });
      },
      onAdImpression: (_) {
        analyticsRepository.sendBannerAdShownEvent();
      },
      onAdOpened: (_) {
        analyticsRepository.sendBannerAdClickEvent();
      },
    );

    bannerAd.load();
  }

  @override
  void dispose() {
    super.dispose();
    anchoredBanner?.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return BlocBuilder<SubscriptionBloc, SubscriptionState>(
      builder: (context, state) {
        final isLoaded = !adLoaded;

        if (isLoaded || state.hasSubscribed || anchoredBanner == null) return SizedBox.shrink();

        return Container(
          color: Colors.transparent,
          width: anchoredBanner!.size.width.toDouble(),
          height: anchoredBanner!.size.height.toDouble(),
          child: Center(
            child: Container(
              color: Colors.white,
              child: AdWidget(
                ad: anchoredBanner!,
              ),
            ),
          ),
        );
      },
    );
  }
}

And this is the repo

class AdMobRepository {
  late String _releaseBannerAdId;
  late String _releaseInterstitualAdId;
  late String _releaseRewardedAdId;

  AdMobRepository() {
    if (Platform.isAndroid) {
      _releaseBannerAdId = Constants.androidBannedAdId;
      _releaseInterstitualAdId = Constants.androidInterstitualAdId;
      _releaseRewardedAdId = Constants.androidRewardedAdId;
    } else if (Platform.isIOS) {
      _releaseBannerAdId = Constants.iosBannerAdId;
      _releaseInterstitualAdId = Constants.iosInterstitualAdId;
      _releaseRewardedAdId = Constants.iosRewardedAdId;
    } else {
      _releaseBannerAdId = "";
      _releaseInterstitualAdId = "";
      _releaseRewardedAdId = "";
    }
  }

  BannerAd getBannerAd({
    required AdSize size,
    void Function(Ad, LoadAdError)? onFailedLoad,
    void Function(Ad)? onLoad,
    void Function(Ad)? onAdOpened,
    void Function(Ad)? onAdImpression,
  }) {
    return BannerAd(
      adUnitId: kReleaseMode ? _releaseBannerAdId : BannerAd.testAdUnitId,
      request: AdRequest(),
      size: size,
      listener: BannerAdListener(
        onAdFailedToLoad: onFailedLoad ?? onFailedLoadFallback,
        onAdLoaded: onLoad,
        onAdImpression: onAdImpression,
        onAdOpened: onAdOpened,
      ),
    );
  }

  void onFailedLoadFallback(Ad ad, LoadAdError error) {
    ad.dispose();
  }

  void getInterstitualAd({required void Function(LoadAdError) onFailedLoad, void Function(InterstitialAd)? onLoad}) {
    InterstitialAd.load(
      adUnitId: kReleaseMode ? _releaseInterstitualAdId : InterstitialAd.testAdUnitId,
      request: AdRequest(),
      adLoadCallback: InterstitialAdLoadCallback(
        onAdLoaded: onLoad ?? onInterstitialAdLoadedFallback,
        onAdFailedToLoad: onFailedLoad,
      ),
    );
  }

  void onInterstitialAdLoadedFallback(InterstitialAd ad) {
    ad.fullScreenContentCallback = FullScreenContentCallback(
      onAdDismissedFullScreenContent: (ad) => ad.dispose(),
      onAdFailedToShowFullScreenContent: (ad, error) => ad.dispose(),
    );
  }

  void getRewardAd({required String userId, required void Function(LoadAdError) onFailedLoad, void Function(RewardedAd)? onLoad}) {
    RewardedAd.load(
      adUnitId: kReleaseMode ? _releaseRewardedAdId : RewardedAd.testAdUnitId,
      request: AdRequest(),
      rewardedAdLoadCallback: RewardedAdLoadCallback(
        onAdLoaded: onLoad ?? onRewardedAdLoadedFallback,
        onAdFailedToLoad: onFailedLoad,
      ),
      serverSideVerificationOptions: ServerSideVerificationOptions(userId: userId),
    );
  }

  void onRewardedAdLoadedFallback(RewardedAd ad) {
    ad.fullScreenContentCallback = FullScreenContentCallback(
      onAdDismissedFullScreenContent: (ad) => ad.dispose(),
      onAdFailedToShowFullScreenContent: (ad, error) => ad.dispose(),
    );
  }
}

[Pielgrin]

I fixed it ! For me the solution was to update app/build.gradle and explicitly this line :

classpath 'com.android.tools.build:gradle:4.1.1' to classpath 'com.android.tools.build:gradle:4.2.2'

[Tobias-Keller]

Getting the same crashes with Flutter (Channel stable, 3.3.0) and google_mobile_ads 2.0.1