[Android] ConcurrentModificationException

[williamleungapptask]

This issue still happens with the 0.10.2 release.
"react-native": "0.63.4",
"@stream-io/flat-list-mvcp": "^0.10.2",

java.util.ConcurrentModificationException: null
    at java.util.ArrayList$Itr.next(ArrayList.java:860)
    at com.facebook.react.uimanager.UIManagerModule.onBatchComplete(UIManagerModule.java:795)
    at com.facebook.react.bridge.NativeModuleRegistry.onBatchComplete(NativeModuleRegistry.java:119)
    at com.facebook.react.bridge.CatalystInstanceImpl$BridgeCallback.onBatchComplete(CatalystInstanceImpl.java:171)
    at com.facebook.react.bridge.queue.NativeRunnable.run(NativeRunnable.java)
    at android.os.Handler.handleCallback(Handler.java:938)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:27)
    at android.os.Looper.loopOnce(Looper.java:226)
    at android.os.Looper.loop(Looper.java:313)
    at com.facebook.react.bridge.queue.MessageQueueThreadImpl$4.run(MessageQueueThreadImpl.java:226)
    at java.lang.Thread.run(Thread.java:920)

[aweffr]

same here
we have this ConcurrentModificationException too
the stacktrace is same:

java.util.ConcurrentModificationException: null
    at java.util.ArrayList$Itr.next(ArrayList.java:860)
    at com.facebook.react.uimanager.UIManagerModule.onBatchComplete(UIManagerModule.java:799)
    at com.facebook.react.bridge.NativeModuleRegistry.onBatchComplete(NativeModuleRegistry.java:119)
    at com.facebook.react.bridge.CatalystInstanceImpl$BridgeCallback.onBatchComplete(CatalystInstanceImpl.java:172)
    at com.facebook.react.bridge.queue.NativeRunnable.run(NativeRunnable.java)
    at android.os.Handler.handleCallback(Handler.java:938)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:27)
    at android.os.Looper.loop(Looper.java:236)
    at com.facebook.react.bridge.queue.MessageQueueThreadImpl$4.run(MessageQueueThreadImpl.java:226)
    at java.lang.Thread.run(Thread.java:923)

[utsavo-afk]

Same issue here, however we are seeing ReanimatedUIManager.java in the stack trace
Any suggestions on fixes?
Fatal Exception: java.util.ConcurrentModificationException at java.util.ArrayList$Itr.next(ArrayList.java:860) at com.facebook.react.uimanager.UIManagerModule.onBatchComplete(UIManagerModule.java:35) at com.facebook.react.uimanager.ReanimatedUIManager.onBatchComplete(ReanimatedUIManager.java) at com.facebook.react.bridge.NativeModuleRegistry.onBatchComplete(NativeModuleRegistry.java:24) at com.facebook.react.bridge.CatalystInstanceImpl$BridgeCallback.onBatchComplete(CatalystInstanceImpl.java:14) at com.facebook.react.bridge.queue.NativeRunnable.run(NativeRunnable.java) at android.os.Handler.handleCallback(Handler.java:938) at android.os.Handler.dispatchMessage(Handler.java:99) at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java) at android.os.Looper.loopOnce(Looper.java:226) at android.os.Looper.loop(Looper.java:313) at com.facebook.react.bridge.queue.MessageQueueThreadImpl$4.run(MessageQueueThreadImpl.java:37) at java.lang.Thread.run(Thread.java:920)

[ponikar]

any updates on this issue?

[larkox]

Looking into the code, it seems part of the problem is that in onBatchComplete on the UIManagerModule.java in React Native, the code iterates over the UIManageModuleListener doing its own stuff. And for some reason, when that is happening, removeUIManagerListener is being called (a listener gets removed while the iterator is executing).

This function is called by in

flat-list-mvcp/android/src/main/java/com/mvcpscrollviewmanager/MvcpScrollViewManagerModule.java

Line 160 in b9abef4

uiManagerModule.removeUIManagerListener(listener);

Funny enough, I don't see any other dependency in our project that uses this function, so not sure if this is a problem with this project, or with React Native handling of these listeners.

Hope this helps to find out the issue!