**java.util.ConcurrentModificationException** inside the IMA SDK when using Singleton AdsLoader in a custom integration (not ExoPlayer)

[Suraj Kr I Engineering]

## Reproduction Steps
1. Initialize a single `AdsLoader` globally.  
2. Request ads for multiple playbacks in quick succession (e.g., RecyclerView or playlist use-case).  
3. Occasionally, the SDK throws `ConcurrentModificationException` from `zzac.zzc`.  

[IMA SDK]

Hi,

Thank you for contacting the IMA SDK support team.

I tried reproducing the ConcurrentModificationException issue you mentioned by simulating multiple rapid ad requests using a single global AdsLoader instance in our sample project. However, I was not able to reproduce the error.

Could you please try reproducing the issue using our sample project. If the problem still occurs, kindly share your sample project reproducible code snippet where this issue happens. This will help us investigate further and assist you better.

Kindly provide the requested details via Reply privately to author option.
 

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IMA SDK Team

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[2025-09-03 14:39:08Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01u5hvZ:ref" (ADR-00331729)

[Suraj Kr I Engineering]

Hi,

Thank you for your prompt response and for attempting to reproduce the `ConcurrentModificationException` issue.

Regarding your suggestion to use a sample project, I would like to ask if you could try reproducing the issue using `incide reclerview` with the same `AdsLoader` instance. This specific scenario might highlight the problem more effectively, as our integration involves similar complex ad loading patterns.

We appreciate your continued support in investigating this matter.

Thanks,

Suraj

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[IMA SDK]

Hi,
As suggested, I attempted to reproduce the issue using a RecyclerView setup where each item triggers an ad request using the same shared AdsLoader instance. Despite simulating rapid and concurrent ad requests—both using threads and during RecyclerView item binding—I was unable to reproduce the ConcurrentModificationException.
As mentioned earlier could you please try reproducing it using our sample project. if the issue persists on your end, we kindly request that you share the sample project to this drive Link with us for further investigation

Kindly provide the requested details via Reply privately to author option

Thanks,
 

IMA SDK Team

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How was our support today?

               

[2025-09-04 12:18:23Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01u5hvZ:ref" (ADR-00331729)