[2020.3] com.unity3d.player.ReflectionHelper$a.<init> fatal exception

Hi, we are facing the following exception in Android, after reviewing firebase dashboard we've found the following stack trace:

Caused by java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference
at com.unity3d.player.ReflectionHelper$a.<init>19)
at com.unity3d.player.ReflectionHelper.getMethodID2)

Fatal Exception: java.lang.Error: FATAL EXCEPTION [Thread-9123]
Unity version : 2020.3.34f1
Android OS: 12

Thanks in advance

 

Hi! We also have a ton of crashes with this stack trace:

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference

  at com.unity3d.player.ReflectionHelper$a.<init>

  at com.unity3d.player.ReflectionHelper.getMethodID

We updated Unity from 2020.1.17f1 to 2020.3.34f1 but it looks like it had no effect on the issue

 

Hi! Do you have any updates on this errors?
We are experiencing the same error on our side

 

We also see very similar fatal exception in Crashlytics Dashboard. The amount of crashes is critical, because of this exception. Will be good Unity developers response to this thread.

96% of crash devices has OS: Android 12
4% of crash devices has OS: Android 13

We are using Unity 2020.3.41f1 version.

Caused by java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference

       at com.unity3d.player.ReflectionHelper$a.<init>(:19)

       at com.unity3d.player.ReflectionHelper.getFieldID(:10)

 

Hi,
I'm currently adding AdMob to my project and I have the same error sometimes, do you use AdMob too ? maybe it's related because I did not have this but before.

 

I have the same issue in 2021.3.13f1. Any updates?

 

I have InApp purchasing in my game v. 4.4.1. WHen game started I got warning message:
Unity IAP: <b>Unity In-App Purchasing</b> requires <b>Unity Gaming Services</b> to have been initialized before use
I added init code:

Code (CSharp):

1. const string k_Environment = "production";
2.  
3. void Initialize(Action onSuccess, Action<string> onError)
4. {
5.     try
6.     {
7.         var options = new InitializationOptions().SetEnvironmentName(k_Environment);
8.  
9.         UnityServices.InitializeAsync(options).ContinueWith(task => onSuccess());
10.     }
11.     catch (Exception exception)
12.     {
13.         onError(exception.Message);
14.     }
15. }
16.  
17. void OnSuccess()
18. {
19.     var text = "Congratulations!\nUnity Gaming Services has been successfully initialized.";
20.     informationText.text = text;
21.     Debug.Log(text);
22. }
23.  
24. void OnError(string message)
25. {
26.     var text = $"Unity Gaming Services failed to initialize with error: {message}.";
27.     informationText.text = text;
28.     Debug.LogError(text);
29. }

And when I added this code I got this error.

Update: when I changed code to

Code (CSharp):

1. const string k_Environment = "production";
2.  
3. async void Initialize(Action onSuccess, Action<string> onError)
4. {
5.     try
6.     {
7.         var options = new InitializationOptions().SetEnvironmentName(k_Environment);
8.  
9.         await UnityServices.InitializeAsync(options);
10.  
11.        OnSuccess();
12.     }
13.     catch (Exception exception)
14.     {
15.         onError(exception.Message);
16.     }
17. }
18.  
19. void OnSuccess()
20. {
21.     var text = "Congratulations!\nUnity Gaming Services has been successfully initialized.";
22.     informationText.text = text;
23.     Debug.Log(text);
24. }
25.  
26. void OnError(string message)
27. {
28.     var text = $"Unity Gaming Services failed to initialize with error: {message}.";
29.     informationText.text = text;
30.     Debug.LogError(text);
31. }

crash stoped.

 

Yes we use AdMob in our project.

 

java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Object.hashCode()' on a null object reference
at com.unity3d.player.ReflectionHelper$a.<init>(Unknown Source:11)
at com.unity3d.player.ReflectionHelper.getMethodID(Unknown Source:2)
unity 2019.4.10 I met the same problem,

 

I also encountered the same problem, but I can't reproduce it locally. Can anyone provide a stable reproduction step?
Unity version : 2020.3.25f1c1
Android OS: 12+
Target:31

Thanks

 

I had Unity Mediation packages residual files + admob, I think the plugins was colliding.
After removing the Unity Mediation files all is ok.

 

Hmm seems I talked too fast, the error is still here, but very rare and I can't find a way to reproduce it.

 

OK, find a way to reproduce the bug using AdMob at 100%

Code (CSharp):

1.  
2.     public void CreateAndLoadRewardedAd()
3.     {
4.         #if UNITY_ANDROID
5.             string adUnitId = "ca-app-pub-3940256099942544/5224354917";
6.         #elif UNITY_IPHONE
7.             string adUnitId = "ca-app-pub-3940256099942544/1712485313";
8.         #else
9.             string adUnitId = "unexpected_platform";
10.         #endif
11.  
12.         this.rewardedAd = new RewardedAd(adUnitId);
13.  
14.         this.rewardedAd.OnAdLoaded += HandleRewardedAdLoaded;
15.         this.rewardedAd.OnUserEarnedReward += HandleUserEarnedReward;
16.         this.rewardedAd.OnAdClosed += HandleRewardedAdClosed;
17.  
18.         // Create an empty ad request.
19.         AdRequest request = new AdRequest.Builder().Build();
20.         // Load the rewarded ad with the request.
21.         this.rewardedAd.LoadAd(request);
22.     }
23.  
24.     public async void HandleRewardedAdClosed(object sender, EventArgs args)
25.     {
26.         await Task.Delay(2000);
27.         CreateAndLoadRewardedAd(); // here the crash happen !
28.     }
29.  

Just trying to reload the ad after an async delay makes the app crash.
In case of load failed I added a reload after a delay and the crash happend in these case.

To fix the issue in this case just use something like https://github.com/PimDeWitte/Unity...b/master/Runtime/UnityMainThreadDispatcher.cs.

So changing the above code with:

Code (CSharp):

1.  
2.     public async void HandleRewardedAdClosed(object sender, EventArgs args)
3.     {
4.         await Task.Delay(2000);
5.         UnityMainThreadDispatcher.Instance().Enqueue( CreateAndLoadRewardedAd ); // no crash here
6.     }
7.  

Fixes the bug.

Hope this could help someone

 

We do not use Admob but we are also getting this error:
Unity 2020.3.30f1

Code (CSharp):

1. Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference
2.   at com.unity3d.player.ReflectionHelper$a.<init>
3.   at com.unity3d.player.ReflectionHelper.getMethodID

 

Do you call native function after an await ?

 

No, we are not using Await/Async.

 

Did you managed to find the problem?

 

After making the update available on the store I have lot of errors spamming in the Android Vital page, I deactivate the ads and the errors stopped.
Anyone finds a way to correct this error ?
Maybe someone from Unity could read this topic and gives some help ?

As I think the bug is related somehow to AdMob I also posted in the AdMob issue tracker:
https://github.com/googleads/googleads-mobile-unity/issues/2480

 

So it didn't worked at the end?

 

It kind of worked as before the fix I had 100% reproductible bug and after I never reproduce it on my test devices. In production I have still some crash because of this bug (1000 crash on 400 unique users on 15 days on my game with near 10000 daily users).
But this bug has caused my game to reach the crash rate limit on google play store, so I had to disable AdMob for the moment. I'm currently trying to resolve the issue (changing ad mediation partner) to be able te re-activate ads on my game.

 

Thank you for your quick answer! We are also trying to fix this errors on our games. If we manage to find something, I will update this thread

We are using Unity 2020.3.38 and ApplovinMAX as mediation of the advertising networks.
We will try to update to 2021.3 on some of our games. But as Unity 2021.3 was shipped with a bugged NDK, we don't want to be based on this version of Unity.
We hope Unity will release an LTS version of 2022 soon

 

I'm currently on the 2021.3.14f1 and I have the bug so no need to upgrade to 2021.3
For the NDK bug, it's a little random, sometimes the build succeed, sometimes not, so I changed the C++ Compiler Configuration to "release" instead of "master", now the build always succeed.

 

Ok good to know! Thanks

Yeah but when you set the C++ Compiler Configuration to `release` it increases the AAB/APK size. In our case we were above the 150MB size limit of GooglePlay console

 

Same issue on my side, has anyone resolved it?

 

BBO_Lagoon can you please confirm if I disable admob plugin, will this crash not happen? I am using 2021.3.16f1 LTS with Google Ads 7.2.0

 

On my game, I disabled the videos (SDK still here but initialisation and ads code is not called) and now the crash don't happen anymore.

 

Ok so it's only Fullscreen ads (Rewarded videos and Interstitial videos). Seems normal as they are using the same code for display

 

Unity 2021.3.11, same issue. No Admob, no Unity Services

 

I am also using Applovin Max SDK ads for my game and I am facing almost same problem. There are a lots of crashes for Android OS version 11 and 12 as reported by play store. Is there any update for this problem?

 

As said here: https://github.com/googleads/googleads-mobile-unity/issues/2480, this could be a Firebase issue, do you use Firebase ?

 

Also running into this today on Unity 2021.3.18f1. Weirdly it's only happening on one build variant (production, not beta) that are fairly similar to each other (same AndroidManifest.xml, etc). We don't use ads, just Unity IAP.

 

This is still happening in Unity 2021.3.21f1 and is going to be a blocker for us. Any ideas? Unity 2022?

 

I sent a report in via the bug reporter. In the meantime I will try Unity 2022.

 

Updating to Unity 2022.2.11f1 seems to have solved this for us.

 

Hello, I had the same crash on a test phase of IAP system. The crash was happening because of a code line just like this one => UnityServices.InitializeAsync(options).ContinueWith(task => onSuccess()); Unity version was 2021.3.16f1.

I think this code causes onSuccess to be called on a thread other than main thread. And since UnityEngine library is not thread safe and not suitable for multithreading it throws an exception. In situations like this usually there is another method named as ContinueWithMainThread() or sth like that.

When I stopped using ContinueWith() method the crash was fixed.

 

I had the problem in async void Awake() calling await UnityServices.InitializeAsync(options);

Still seems happy on Unity 2022 so we're going with that.

 

Hi everyone, I am from the same company that Edgar, the starter of this thread.

We found a solution for this issue, in our case the problem was caused because some metrics were tracked in other threads that was not the MainThread. We use UniRX in our project and we think that this could be related to this issue.

The recommendation is to check the events of firebase (or other metric software, we have 4 different in our project) and force this process to go through the MainThread of Unity.

Every call of native java code in Unity must go through the MainThread or has to be attached with AttachCurrentThread() method.

I hope this could help someone. Thank everyone for the help and research!

 

The error went away for us, I only did 2 things.

I added more switching to main thread during advert loading and showing but my testers were still able to crash the build (I didn't release to users).

I also turned incremental GC back on (I had turned it off at the same time the errors started comming in), i released this and that specific crash seems to have gone away (although GC_locks are back.

 

This solution helped me, I had a problem after updating to Unity 2021.3.16. It was associated with Firebase.FirebaseAppCheckAndFixDependenciesAsync(). ContinueWit() after switching to ContinueWithOnMainThread() the problem disappeared.