Main thread can be blocked sometimes

[VolodaUa]

Expected behavior

The main thread should not be blocked.

Actual behavior

Sometimes main thread is blocked on region changing.

Steps to reproduce this behavior

It happens randomly and I can't provide any steps. I am near two iBeacons.

Stack trace

"main@33652" prio=5 tid=0x2 nid=NA waiting for monitor entry
java.lang.Thread.State: BLOCKED
blocks pool-29-thread-1@33728
waiting for pool-29-thread-1@33728 to release lock on <0x83c2> (a org.altbeacon.beacon.service.MonitoringStatus)
at org.altbeacon.beacon.service.MonitoringStatus.regions(MonitoringStatus.java:88)
at org.altbeacon.beacon.service.ScanState.restore(ScanState.java:181)
- locked <0x6bac> (a java.lang.Class)
at org.altbeacon.beacon.service.ScanJobScheduler.scheduleAfterBackgroundWakeup(ScanJobScheduler.java:133)
at org.altbeacon.beacon.startup.StartupBroadcastReceiver.onReceive(StartupBroadcastReceiver.java:62)
at android.app.ActivityThread.handleReceiver(ActivityThread.java:4490)
at android.app.ActivityThread.-$$Nest$mhandleReceiver(ActivityThread.java:-1)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2281)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loopOnce(Looper.java:205)
at android.os.Looper.loop(Looper.java:294)
at android.app.ActivityThread.main(ActivityThread.java:8248)
at java.lang.reflect.Method.invoke(Method.java:-1)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

Mobile device model and OS version

Google Pixel 7 Pro, Android 14

Android Beacon Library version

Android Beacon Library 2.20.4
Java 17

IMPORTANT: This forum is reserved for feature requests or reproducible bugs with the library itself. If you need help with using the library with your project, please open a new question on StackOverflow.com.

[tabere-ubique]

This is still happening in 2.21.1 and I am not sure how to reproduce those either. But most of the stacktraces look like that:

          main (native):tid=1 systid=23383 
#00 pc 0x9aedc libc.so (syscall + 28) (BuildId: 8dc8afb9a8c98d2a9ecf47561e4816e1)
#01 pc 0x201230 libart.so (art::ConditionVariable::WaitHoldingLocks + 136) (BuildId: eb4ec0f1d1c7267591d83fa87cb36390)
#02 pc 0x663754 libart.so (art::JNI<false>::ReleaseByteArrayElements + 1936) (BuildId: eb4ec0f1d1c7267591d83fa87cb36390)
#03 pc 0x2ce94 libjavacore.so (Linux_readBytes + 348) (BuildId: 3f93db2ad70bc256fba2c6b9b963d704)
       at libcore.io.Linux.readBytes(Native method)
       at libcore.io.Linux.read(Linux.java:229)
       at libcore.io.ForwardingOs.read(ForwardingOs.java:618)
       at libcore.io.BlockGuardOs.read(BlockGuardOs.java:325)
       at libcore.io.ForwardingOs.read(ForwardingOs.java:618)
       at libcore.io.IoBridge.read(IoBridge.java:604)
       at java.io.FileInputStream.read(FileInputStream.java:353)
       at java.io.FileInputStream.read(FileInputStream.java:291)
       at java.io.ObjectInputStream$PeekInputStream.peek(ObjectInputStream.java:2654)
       at java.io.ObjectInputStream$BlockDataInputStream.peek(ObjectInputStream.java:2961)
       at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2971)
       at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1408)
       at java.io.ObjectInputStream.readObject(ObjectInputStream.java:430)
       at java.util.HashMap.readObject(HashMap.java:1558)
       at java.lang.reflect.Method.invoke(Native method)
       at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1109)
       at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2085)
       at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1935)
       at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1442)
       at java.io.ObjectInputStream.readObject(ObjectInputStream.java:430)
       at java.util.HashMap.readObject(HashMap.java:1558)
       at java.lang.reflect.Method.invoke(Native method)
       at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1109)
       at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2085)
       at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1935)
       at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1442)
       at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2186)
       at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2110)
       at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1935)
       at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1442)
       at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2186)
       at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2110)
       at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1935)
       at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1442)
       at java.io.ObjectInputStream.readObject(ObjectInputStream.java:430)
       at org.altbeacon.beacon.service.ScanState.restore(ScanState.java:145)
       at org.altbeacon.beacon.service.ScanJobScheduler.scheduleAfterBackgroundWakeup(ScanJobScheduler.java:133)
       at org.altbeacon.beacon.startup.StartupBroadcastReceiver.onReceive(StartupBroadcastReceiver.java:62)
       at android.app.ActivityThread.handleReceiver(ActivityThread.java:5090)
       at android.app.ActivityThread.-$$Nest$mhandleReceiver(unavailable)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2584)
       at android.os.Handler.dispatchMessage(Handler.java:110)
       at android.os.Looper.dispatchMessage(Looper.java:315)
       at android.os.Looper.loopOnce(Looper.java:251)
       at android.os.Looper.loop(Looper.java:349)
       at android.app.ActivityThread.main(ActivityThread.java:9041)
       at java.lang.reflect.Method.invoke(Native method)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:593)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:929)