ConcurrentModificationException

[472574155]

Describe the bug
When multiSubscription using, unexpectly exception happened.

To Reproduce
Steps to reproduce the behavior:
When net changed, easily happened

Expected behavior
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:851)
at java.util.HashMap$KeyIterator.next(HashMap.java:885)
at com.amazonaws.mobileconnectors.appsync.subscription.RealSubscriptionManager$1.onError(RealSubscriptionManager.java:196)
at com.amazonaws.mobileconnectors.appsync.subscription.mqtt.MqttSubscriptionClient$1.onFailure(MqttSubscriptionClient.java:85)
at org.eclipse.paho.android.service.MqttTokenAndroid.notifyFailure(MqttTokenAndroid.java:146)
at org.eclipse.paho.android.service.MqttAndroidClient.simpleAction(MqttAndroidClient.java:1501)
at org.eclipse.paho.android.service.MqttAndroidClient.connectAction(MqttAndroidClient.java:1439)
at org.eclipse.paho.android.service.MqttAndroidClient.onReceive(MqttAndroidClient.java:1368)
at android.support.v4.content.LocalBroadcastManager.executePendingBroadcasts(LocalBroadcastManager.java:297)
at android.support.v4.content.LocalBroadcastManager.access$000(LocalBroadcastManager.java:46)
at android.support.v4.content.LocalBroadcastManager$1.handleMessage(LocalBroadcastManager.java:116)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6242)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:889)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:779)

Environment(please complete the following information):

• AppSync SDK Version: [2.6.+]

Device Information (please complete the following information):

• Device: SHAPE AQUOS SH-M05
• Android Version: [Nougat 7.1.2]

[scb01]

@472574155

Sorry to hear that you are running into issues. Can you confirm that you are on the latest version of the SDK (2.6.26)? The latest version contains bug fixes for multiple subscriptions - my inspection of the stacktrace is leading me to believe that you may be on an older rev of the SDK. Line 196 of the latest RealSubscriptionManager code is now

aws-mobile-appsync-sdk-android/aws-android-sdk-appsync/src/main/java/com/amazonaws/mobileconnectors/appsync/subscription/RealSubscriptionManager.java

Line 196 in 3b120e9

Set<SubscriptionObject> subscriptionObjects =

If you are on an older version, can you upgrade and let us know it goes.

[472574155]

@cbommas

Thanks for answer. The reason is that maven is not the lastest version.

classpath 'com.amazonaws:aws-android-sdk-appsync-gradle-plugin:2.6.+'

apply plugin: 'com.amazonaws.appsync'
implementation 'com.amazonaws:aws-android-sdk-appsync:2.6.26'

When using gradle to import, code is not the lastest!
Maven is not the lastest version.

Maven url:http://central.maven.org/maven2/com/amazonaws/aws-android-sdk-appsync/2.6.26/aws-android-sdk-appsync-2.6.26-sources.jar

[scb01]

@472574155
I double checked Maven and tried to reproduce the error, however I wasn't able to.
Can you share your build.gradle file?

My build.gradle contains

      implementation "com.amazonaws:aws-android-sdk-appsync-gradle-plugin:2.6.+"
      implementation "com.amazonaws:aws-android-sdk-appsync:2.6.+"

and this pulls down the latest version when I do a gradle sync.
Also, please do let me know if you are still experiencing the issue with the latest version.

[472574155]

@cbommas
This issue still happened.
My build.gradle contains

implementation 'com.amazonaws:aws-android-sdk-appsync:2.6.26'
implementation 'com.amazonaws:aws-android-sdk-s3:2.7.2'
implementation 'com.amazonaws:aws-android-sdk-cognito:2.6.30'
implementation 'com.amazonaws:aws-android-sdk-mobile-client:2.6.31'
implementation 'com.amazonaws:aws-android-sdk-cognitoidentityprovider:2.7.2'
implementation 'com.amazonaws:aws-android-sdk-sns:2.6.+'

implementation 'com.amazonaws:aws-android-sdk-core:2.7.2'
implementation 'com.amazonaws:aws-android-sdk-ddb:2.6.31'
implementation 'com.google.firebase:firebase-messaging:17.3.4'
implementation 'com.google.firebase:firebase-core:16.0.4'

implementation 'org.eclipse.paho:org.eclipse.paho.client.mqttv3:1.2.0'
implementation 'org.eclipse.paho:org.eclipse.paho.android.service:1.1.1'

[472574155]

@cbommas
Have you checked the jar file?
http://central.maven.org/maven2/com/amazonaws/aws-android-sdk-appsync/2.6.26/aws-android-sdk-appsync-2.6.26-sources.jar (Is maven url right?)

1. download file aws-android-sdk-appsync-2.6.26-sources.jar
2. (.jar) -> (.zip)
3. unzip file
   4.find file (aws-android-sdk-appsync-2.6.26-sources⁩ ▸ ⁨com⁩ ▸ ⁨amazonaws⁩ ▸ ⁨mobileconnectors⁩ ▸ ⁨appsync⁩ ▸ ⁨subscription⁩ ▸ RealSubscriptionManager.java)
   5.line No.196

[scb01]

@472574155
Thank you for pointing this out. I was able to track it down -the code in the github repo was updated after the v2.6.26 release as part of this PR #41 which contains the fix for the issue you are seeing.

Sorry about the confusion. I will get this released in the next few days and will post back on this thread once the release is completed.

[scb01]

@472574155
v2.6.27 is released and contains the fix. Can you please let us know how it goes with the latest rev of the SDK.

[472574155]

@cbommas thanks.