IssueTracker

Have same problem

java.util.ConcurrentModificationException
        at java.util.WeakHashMap$HashIterator.next(WeakHashMap.java:165)
        at androidx.work.impl.utils.WakeLocks.checkWakeLocks(WakeLocks.java:70)
        at androidx.work.impl.background.systemalarm.SystemAlarmService.onAllCommandsCompleted(SystemAlarmService.java:69)
        at androidx.work.impl.background.systemalarm.SystemAlarmDispatcher.dequeueAndCheckForCompletion(SystemAlarmDispatcher.java:217)
        at androidx.work.impl.background.systemalarm.SystemAlarmDispatcher$DequeueAndCheckForCompletion.run(SystemAlarmDispatcher.java:317)
        at android.os.Handler.handleCallback(Handler.java:615)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:4960)
        at java.lang.reflect.Method.invokeNative(Method.java)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
        at dalvik.system.NativeStart.main(NativeStart.java)

Will this be released in the next beta? Thanks

Yes, it will.

Seems like it's still not fixed:

Fatal Exception: java.util.ConcurrentModificationException
       at java.util.WeakHashMap$HashIterator.next(WeakHashMap.java:165)
       at androidx.work.impl.utils.WakeLocks.checkWakeLocks(WakeLocks.java:78)
       at androidx.work.impl.background.systemalarm.SystemAlarmService.onAllCommandsCompleted(SystemAlarmService.java:69)
       at androidx.work.impl.background.systemalarm.SystemAlarmDispatcher.dequeueAndCheckForCompletion(SystemAlarmDispatcher.java:217)
       at androidx.work.impl.background.systemalarm.SystemAlarmDispatcher$DequeueAndCheckForCompletion.run(SystemAlarmDispatcher.java:317)
       at android.os.Handler.handleCallback(Handler.java:810)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:189)
       at android.app.ActivityThread.main(ActivityThread.java:5532)
       at java.lang.reflect.Method.invoke(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:372)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:950)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:745)

Still happened on beta02, Android 5.0.2

Sample app here: https://issuetracker.google.com/issues/121345393

It's hard to reproduce with SystemAlarmService.onAllCommandsCompleted. Only managed to do it once but it was just luck. The sample app crashes more often though.

I meant this url: https://github.com/rubensousa/WorkManagerConcurrent

Thanks for the bug report and the sample app. Will take another look.

Why are you calling a hidden method (WakeLocks#checkWakeLocks) yourself?

Just to reproduce the crash faster. I don't call this on the production app.

The fix will be available in beta03: https://android-review.googlesource.com/c/platform/frameworks/support/+/876992

Thanks a lot for fixing it quickly ;)

It still seems to happen for me using beta02:

java.util.WeakHashMap$HashIterator.next (WeakHashMap.java:165)
androidx.work.impl.utils.WakeLocks.checkWakeLocks (WakeLocks.java:78)
androidx.work.impl.background.systemalarm.SystemAlarmService.onAllCommandsCompleted (SystemAlarmService.java:69)
androidx.work.impl.background.systemalarm.SystemAlarmDispatcher.dequeueAndCheckForCompletion (SystemAlarmDispatcher.java:217)
androidx.work.impl.background.systemalarm.SystemAlarmDispatcher$DequeueAndCheckForCompletion.run (SystemAlarmDispatcher.java:317)
android.os.Handler.handleCallback (Handler.java:815)
android.os.Handler.dispatchMessage (Handler.java:104)
android.os.Looper.loop (Looper.java:194)
android.app.ActivityThread.main (ActivityThread.java:5624)
java.lang.reflect.Method.invoke (Method.java)
java.lang.reflect.Method.invoke (Method.java:372)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:959)
com.android.internal.os.ZygoteInit.main (ZygoteInit.java:754)

Stacktrace is from a X5pro running Android 5.1.

Another fix will be available in beta03.

Thank you. Can you please point me to the commit/file which represents the configuration for WorkManager 1.0.0-alpha09? Maybe here https://android.googlesource.com/platform/frameworks/support/+log/androidx-master-dev/work/workmanager/proguard-rules.pro?

There isn't one for alpha09... it's already released.  You can modify that commit and adapt it to alpha09.

Just change WorkParameters -> WorkerParameters.

Which commit do you refer to? The link I posted show the history of the proguard-rules.pro commits. Since the file exists for a year I would have expected that there was a version of the file which shipped with WorkManager 1.0.0-alpha which was released by September 19, 2018.

Or do you mean that the proguard-rules.pro being shipped with WorkManager 1.0.0-alpha is buggy?

Yes, alpha09 had a bug.  #19 suggests a modification to your app's proguard config to get around the issue.  alpha10 should be out soon with the fix.

Thank you for the clarification.

I prepared my test branch according to your recommendations (ProGuard, compileSdkVersion, targetSdkVersion, support libraries) as you can see here:
https://github.com/EventFahrplan/EventFahrplan/compare/master...workmanager

The release build however still fails:

00:20:09.182 [QUIET] [system.out] Note: androidx.work.impl.Schedulers: can't find dynamically referenced class androidx.work.impl.background.firebase.FirebaseJobService
00:20:09.182 [QUIET] [system.out] Note: androidx.work.impl.Schedulers: can't find dynamically referenced class androidx.work.impl.background.firebase.FirebaseJobScheduler
00:20:09.210 [QUIET] [system.out] Note: kotlin.internal.PlatformImplementationsKt: can't find dynamically referenced class kotlin.internal.jdk8.JDK8PlatformImplementations
00:20:09.210 [QUIET] [system.out] Note: kotlin.internal.PlatformImplementationsKt: can't find dynamically referenced class kotlin.internal.JRE8PlatformImplementations
00:20:09.210 [QUIET] [system.out] Note: kotlin.internal.PlatformImplementationsKt: can't find dynamically referenced class kotlin.internal.jdk7.JDK7PlatformImplementations
00:20:09.210 [QUIET] [system.out] Note: kotlin.internal.PlatformImplementationsKt: can't find dynamically referenced class kotlin.internal.JRE7PlatformImplementations
00:20:09.212 [QUIET] [system.out] Note: kotlin.jvm.internal.Reflection: can't find dynamically referenced class kotlin.reflect.jvm.internal.ReflectionFactoryImpl
00:20:09.228 [QUIET] [system.out] Note: okhttp3.internal.platform.AndroidPlatform: can't find dynamically referenced class com.android.org.conscrypt.SSLParametersImpl
00:20:09.228 [QUIET] [system.out] Note: okhttp3.internal.platform.AndroidPlatform: can't find dynamically referenced class org.apache.harmony.xnet.provider.jsse.SSLParametersImpl
00:20:09.228 [QUIET] [system.out] Note: okhttp3.internal.platform.AndroidPlatform$CloseGuard: can't find dynamically referenced class dalvik.system.CloseGuard
00:20:09.228 [QUIET] [system.out] Note: okhttp3.internal.platform.ConscryptPlatform: can't find dynamically referenced class org.conscrypt.ConscryptEngineSocket
00:20:09.229 [QUIET] [system.out] Note: okhttp3.internal.platform.Platform: can't find dynamically referenced class sun.security.ssl.SSLContextImpl
00:20:09.955 [QUIET] [system.out] Note: the configuration keeps the entry point 'androidx.core.graphics.drawable.IconCompatParcelizer { android.support.v4.graphics.drawable.IconCompat read(androidx.versionedparcelable.VersionedParcel); }', but not the descriptor class 'androidx.versionedparcelable.VersionedParcel'
00:20:09.955 [QUIET] [system.out] Note: the configuration keeps the entry point 'androidx.core.graphics.drawable.IconCompatParcelizer { void write(android.support.v4.graphics.drawable.IconCompat,androidx.versionedparcelable.VersionedParcel); }', but not the descriptor class 'androidx.versionedparcelable.VersionedParcel'

These aren't failures (unless your configuration has a problem).  As you can see, you have things listed from other libraries like okhttp as well.

Maybe, I missing the specific part in the output. I pasted a large part of the lower end here: http://pastebin.de/8421/

You need to add:

-dontwarn sun.misc.Unsafe

Thank you. This made the release build succeed.
Can you please explain which library (version) introduces the Unsafe class?

I am still facing this issue with WorkManager-1.0.0-beta01

2018-12-31 01:40:32.701 2947-2977/de.aurora.mggvertretungsplan.debug E/WM-WorkerFactory: Could not instantiate de.aurora.mggvertretungsplan.services.DownloadTimeTableWorker
    java.lang.IllegalAccessException: Class java.lang.Class<androidx.work.WorkerFactory> cannot access  method void de.aurora.mggvertretungsplan.services.DownloadTimeTableWorker.<init>(android.content.Context, androidx.work.WorkerParameters) of class java.lang.Class<de.aurora.mggvertretungsplan.services.DownloadTimeTableWorker>
        at java.lang.reflect.Constructor.newInstance0(Native Method)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
        at androidx.work.WorkerFactory.createWorkerWithDefaultFallback(WorkerFactory.java:92)
        at androidx.work.impl.WorkerWrapper.runWorker(WorkerWrapper.java:191)
        at androidx.work.impl.WorkerWrapper.run(WorkerWrapper.java:125)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:764)
2018-12-31 01:40:32.701 2947-2977/de.aurora.mggvertretungsplan.debug E/WM-WorkerWrapper: Could not create Worker de.aurora.mggvertretungsplan.services.DownloadTimeTableWorker

My code can be found at https://github.com/d-Rickyy-b/MGGVertretungsplan.

I'd be very grateful for any kind of support.

Okay... I feel pretty stupid now - it seems that my constructor was package-private and for workmanager to work, it needed to be public. Maybe the exception could point to that issue?

That is correct. Worker must have a public constructor unless you instantiate it via your own WorkerFactory.