ConcurrentModificationException Crashes in GAM SDK Version v24.5.0

[Bhavesh Solanki]

Hi Google Mobile Ads SDK Team,

We are encountering a recurring ConcurrentModificationException crash in our production app, and the stack trace shows it is occurring inside the Google Mobile Ads SDK.

Fatal Exception: java.util.ConcurrentModificationException
    at android.util.ArrayMap.put(ArrayMap.java:627)
    at android.os.BaseBundle.putLong(BaseBundle.java:913)
    at com.google.android.gms.internal.ads.zzdlm.zzb(com.google.android.gms:play-services-ads@@...)
    at com.google.android.gms.internal.ads.zzgdk.run(com.google.android.gms:play-services-ads@@...)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1156)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:651)
    at java.lang.Thread.run(Thread.java:1119)

Observations

• The crash appears to be caused by multi-threaded access to shared SDK state, specifically an ArrayMap (via BaseBundle) being accessed and modified concurrently.

• This is happening inside SDK internal classes and not triggered directly by our app logic.

Impact

• We cannot reliably reproduce it in a sample project because it happens under specific runtime conditions within the SDK.

• This is a high-priority blocker for us.

Request

We request that this be investigated on priority. Since the stack trace points to exact internal classes and methods, we believe your engineering team can track down the root cause without a reproducible sample from our side.

Thanks,

Bhavesh.

[Mobile Ads SDK Forum Advisor]

Hi,
Thank you for reaching out to the Mobile Ads SDK Support team.

The investigation is still ongoing. I’ll be sure to get back to you as soon as I receive any updates from the wider team.

Thanks,
 

Mobile Ads SDK Team

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[2025-08-11 05:21:57Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01syfNE:ref" (ADR-00329454)

[Mobile Ads SDK Forum Advisor]

Hi,

The ConcurrentModificationException should be resolved in 24.5.0 release. I would suggest to upgrade to the latest version of SDK and get back to us if you encounter this issue again. 

Thanks,
 

Mobile Ads SDK Team

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How was our support today?

               

[2025-10-06 20:56:26Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01syfNE:ref" (ADR-00329454)