🐞[Fatal Exception: java.lang.NullPointerException Attempt to read from field 'java.lang.String io.flutter.view.FlutterCallbackInformation.callbackLibraryPath' on a null object reference in method 'java.lang.String DartExecutor$DartCallback.toString()'] #650
Description
- I have read the README
- I have done the setup for Android
- I have done the setup for iOS
- I have ran the sample app and it does not work there
Version
| Technology | Version |
|---|---|
| Workmanager version | 0.8.0 |
Describe the error
Fatal Exception: java.lang.NullPointerException: Attempt to read from field 'java.lang.String io.flutter.view.FlutterCallbackInformation.callbackLibraryPath' on a null object reference in method 'java.lang.String io.flutter.embedding.engine.dart.DartExecutor$DartCallback.toString()'
at io.flutter.embedding.engine.dart.DartExecutor$DartCallback.toString(DartExecutor.java:426)
at java.lang.String.valueOf(String.java:4112)
at java.util.Objects.toString(Objects.java:147)
at io.flutter.embedding.engine.dart.DartExecutor.executeDartCallback(DartExecutor.java:181)
at dev.fluttercommunity.workmanager.BackgroundWorker.startWork$lambda$5(BackgroundWorker.kt:111)
at android.os.Handler.handleCallback(Handler.java:958)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:230)
at android.os.Looper.loop(Looper.java:319)
at android.app.ActivityThread.main(ActivityThread.java:8919)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:578)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1103)
Describe error:
I believe the error occurs when the Android plugin attempts to retrieve a Flutter Dart entry callback, which is unavailable due to factors such as the method not existing or the app having multiple processes. We’ve also observed this issue in our in-house plugin, which creates a headless Flutter engine in Android services running in another process. When trying to retrieve the saved Flutter callback, the other process fails and returns a null value, while the main process succeeds.