Crashes because of latest version - 24.2.0

[Ayushi Khandelwal]

Issue #1 -  
  Fatal Exception: java.util.ConcurrentModificationException:
       at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1111)
       at java.util.ArrayList$Itr.next(ArrayList.java:1064)
       at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1123)
       at com.google.android.gms.internal.ads.zzfkz.zze(com.google.android.gms:play-services-ads@@24.2.0:3)
       at com.google.android.gms.internal.ads.zzfkm.run(com.google.android.gms:play-services-ads@@24.2.0:3)
       at java.lang.Thread.run(Thread.java:1012)







Issue #2 -

          Fatal Exception: java.util.ConcurrentModificationException:
       at java.util.ArrayList$Itr.next(ArrayList.java:860)
       at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1089)
       at com.google.android.gms.internal.ads.zzfkz.zze(com.google.android.gms:play-services-ads@@24.2.0:3)
       at com.google.android.gms.internal.ads.zzfkm.run(com.google.android.gms:play-services-ads@@24.2.0:3)
       at java.lang.Thread.run(Thread.java:923)

[Mobile Ads SDK Forum Advisor]

Hi,

Thank you for contacting the Mobile Ads SDK Support team.

Could you confirm whether the mentioned issue is reproducible in our sample project? kindly provide the below information privately for further investigation:

• Sample project reproducing the issue
• The full Crash logs
• Steps to replicate the issue
• Affected devices

If the file(s) you are looking to share are less than 25mb in total you can attach them to this case on your next reply. If you are having trouble attaching your file to this case or if your file(s) are larger than 25mb, you can share your files via reply to author or by performing the following steps:

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Thanks,
 

Mobile Ads SDK Team

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[2025-04-22 13:18:56Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01qUXer:ref" (ADR-00300676)

[Ayushi Khandelwal]

It’s happening randomly—I don’t have definite steps to reproduce the issue.
It has been reported across all Android operating systems from version 7 to 15.

[Mobile Ads SDK Forum Advisor]

Hi Ayushi,

Thanks for getting back to us.

As previously mentioned, we tested the issue using the Google sample project but were unable to replicate the problem. Based on the provided error details, it appears that the issue is related to an integration problem within your application. The ConcurrentModificationException typically occurs when a collection is modified while it is being iterated over. Could you confirm if you’ve observed the same behavior in our Google sample application? If yes, then In order to make progress on this issue we would require the requested details to conduct thorough investigation. 

• Sample project reproducing the issue

If the file(s) you are looking to share are less than 25mb in total you can attach them to this case on your next reply. If you are having trouble attaching your file to this case or if your file(s) are larger than 25mb, you can share your files with me by performing the following steps:
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Thanks,
 

Mobile Ads SDK Team

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[2025-04-23 07:19:02Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01qUXer:ref" (ADR-00300676)

[mianha...@gmail.com]

we are also facing same issue 

          Fatal Exception: java.util.ConcurrentModificationException:
       at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1111)
       at java.util.ArrayList$Itr.next(ArrayList.java:1064)
       at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1123)
       at com.google.android.gms.internal.ads.zzfkz.zze(com.google.android.gms:play-services-ads@@24.2.0:3)
       at com.google.android.gms.internal.ads.zzfkm.run(com.google.android.gms:play-services-ads@@24.2.0:3)
       at java.lang.Thread.run(Thread.java:1012)

[mianha...@gmail.com]

          Fatal Exception: java.util.ConcurrentModificationException:
       at java.util.ArrayList$Itr.next(ArrayList.java:860)
       at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1089)

       at com.google.android.gms.internal.ads.zzfkz.zze(com.google.android.gms:play-services-ads@@24.2.0:3)
       at com.google.android.gms.internal.ads.zzfkm.run(com.google.android.gms:play-services-ads@@24.2.0:3)

       at java.lang.Thread.run(Thread.java:919)

[Mobile Ads SDK Forum Advisor]

Hi,

Thank you for contacting the Mobile Ads SDK Support team.

Could you confirm whether the mentioned issue is reproducible in our sample project? kindly provide the below information privately for further investigation:

• Sample project reproducing the issue

• The full Crash logs
• Steps to replicate the issue
• Affected devices

If the file(s) you are looking to share are less than 25mb in total you can attach them to this case on your next reply. If you are having trouble attaching your file to this case or if your file(s) are larger than 25mb, you can share your files via reply to author or by performing the following steps:

1. Navigate to
https://docs.google.com/forms/d/e/1FAIpQLSfkAiXMeYP-fw1W3Z-tT9uwmATEKO5X6S-th0gR2ezdKaaqfg/viewform?usp=pp_url&entry.400550049=Mobile+Ads+SDK&entry.460850823=500Ht00001qUXerIAG&entry.80707362=00300676

2. Fill out all fields, and attach your file(s).

3. Please reply back on this thread when you have uploaded your file(s). Please do not share this link.

 

Thanks,
 

Mobile Ads SDK Team

Feedback
How was our support today?

               

[2025-04-28 04:58:56Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01qUXer:ref" (ADR-00300676)

[mianha...@gmail.com]

This is a random crash , happening on the new sdk version 24.2.0 and we are unable to reproduce it on the app.

[Mobile Ads SDK Forum Advisor]

Hi,

For us to check and investigate we need the earlier requested details. As with the mentioned version we are unable to reproduce the issue.

If the file(s) you are looking to share are less than 25mb in total you can attach them to this case on your next reply. If you are having trouble attaching your file to this case or if your file(s) are larger than 25mb, you can share your files via reply to author or by performing the following steps:
1. Navigate to
https://docs.google.com/forms/d/e/1FAIpQLSfkAiXMeYP-fw1W3Z-tT9uwmATEKO5X6S-th0gR2ezdKaaqfg/viewform?usp=pp_url&entry.400550049=Mobile+Ads+SDK&entry.460850823=500Ht00001qUXerIAG&entry.80707362=00300676
2. Fill out all fields, and attach your file(s).

3. Please reply back on this thread when you have uploaded your file(s). Please do not share this link.

Thanks,
 

Mobile Ads SDK Team

Feedback
How was our support today?

               

[2025-04-28 21:51:33Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01qUXer:ref" (ADR-00300676)

[mianha...@gmail.com]

we have rolled back to admob sdk version  24.1.0 and we are not facing this crash now, this shows that crash is in the  24.2.0 version.

[Mobile Ads SDK Forum Advisor]

Hi,

I can understand your concern, can you tell us when loading which ad type you are getting cash? provide below details.

• App Id
• AdUnit ID
• Any other additional logs
• Impacted devices

Thanks,
 

Mobile Ads SDK Team

Feedback
How was our support today?

               

[2025-05-05 22:27:32Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01qUXer:ref" (ADR-00300676)

[Maciej S]

Hi, 

we are facing the same two crashes mentioned in this thread after implementing AdMob native ads:

Fatal Exception: java.util.ConcurrentModificationException:
       at java.util.ArrayList$Itr.next(ArrayList.java:860)
       at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1089)

       at com.google.android.gms.internal.ads.zzfkz.zze(zzfkz.java:3)
       at com.google.android.gms.internal.ads.zzfkm.run(zzfkm.java:3)
       at java.lang.Thread.run(Thread.java:920)

and

Fatal Exception: java.util.ConcurrentModificationException:
       at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1111)
       at java.util.ArrayList$Itr.next(ArrayList.java:1064)
       at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1123)

       at com.google.android.gms.internal.ads.zzfkz.zze(zzfkz.java:3)
       at com.google.android.gms.internal.ads.zzfkm.run(zzfkm.java:3)
       at java.lang.Thread.run(Thread.java:1012)

So far we were not able to reproduce the issue on our end.

We are currently using 23.4.0 version of the lib, another issue (https://issuetracker.google.com/issues/381127096) prevents us from upgrading. We see the crashes across different devices and Android versions.

We load 2 ads at a time, like so:

override suspend fun getNativeAds(unitId: UnitId, numberOfAds: Int): List<AdmobNativeAdUi> =
suspendCancellableCoroutine { continuation ->
val ads = mutableListOf<AdmobNativeAdUi>()
var adLoader: AdLoader? = null

adLoader = AdLoader.Builder(application, unitId.unitId)
.forNativeAd { ad ->
if (continuation.isActive) {
val adModel = AdmobNativeAdUi(ad)
ads.add(adModel)

if (adLoader?.isLoading == false) {
continuation.resume(ads)
}
} else {
ad.destroy()
ads.destroy()
}
}
.withAdListener(object : AdListener() {
override fun onAdFailedToLoad(adError: LoadAdError) {
if (continuation.isActive) {
continuation.resumeWithException(IOException(adError.toString()))
}
}
})
.withNativeAdOptions(
NativeAdOptions.Builder().build()
)
.build()

continuation.invokeOnCancellation {
ads.destroy()
}

adLoader.loadAds(AdRequest.Builder().build(), numberOfAds)
}

We invoke this from a single place, protected with a mutex, and with a timeout, like so:

mutex.withLock {

...

    withTimeout(timeout) {

        val ads = getNativeAds(numberOfAds = 2, ...)

    }

}

We display the ads inside a lazylist, inserted between other content on the screen. 

Can you spot any issues with the way we integrated the SDK? Any help would be appreciated.

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