Hi, FYI, I edited my message on the Nabble archive website because I realised I sent the wrong stack trace at first (but I don't know if you've noticed the modification). The first one was actually related to a custom Sink function that sends data to the Eventhub (not sure whether they are related issues or not)
The one related to the source is the following: Exception in thread "Thread-2" java.lang.NoClassDefFoundError: com/microsoft/azure/eventhubs/MessageReceiver$10 at com.microsoft.azure.eventhubs.MessageReceiver.scheduleLinkCloseTimeout(MessageReceiver.java:574) at com.microsoft.azure.eventhubs.MessageReceiver.onClose(MessageReceiver.java:641) at com.microsoft.azure.eventhubs.ClientEntity.close(ClientEntity.java:78) at com.microsoft.azure.eventhubs.PartitionReceiver.onClose(PartitionReceiver.java:391) at com.microsoft.azure.eventhubs.ClientEntity.close(ClientEntity.java:78) at com.microsoft.azure.eventhubs.ClientEntity.closeSync(ClientEntity.java:93) at commons.source.azure.eventhub.PartitionPoller.shutdown(PartitionPoller.java:80) at commons.source.azure.eventhub.PartitionPoller.run(PartitionPoller.java:55) Caused by: java.lang.ClassNotFoundException: com.microsoft.azure.eventhubs.MessageReceiver$10 at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ... 8 more I don't know if I exactly understand what you mean by " trying to use the Thread Context ClassLoader" (I do not have a deep knowledge related to ClassLoader) but I am not calling explicitly any method on the Thread Context ClassLoader and by going through the different methods of the stack trace I did not notice any neither. As I was explaining at first, within the source I basically create a thread that is constantly polling messages from the Eventhub (like the KafkaConsummerThread is doing with kafka) using Microsoft library. Under the hood, Microsoft uses some threadPoolExecutor and the proton library. The whole source works fine except that I get those ClassNotFoundException from time to time with no real apparent reason. I use Flink Version: 1.3.2 Best, Romain -- Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/