Hi All, We came across an issue with Hazelcast topics when passing custom message objects (Can occur for Maps and all the other data structures in Hazelcast) with C5 Hazelcast module. We have created an issue for this as well [1]. Use case
I'm working with Hazelcast reliable topics in an OSGi environment. I'm using a custom message object with Hazelcast topics ClusterNotification <https://github.com/wso2/andes/blob/v3.1.5/modules/andes-core/broker/src/main/java/org/wso2/andes/server/cluster/coordination/ClusterNotification.java> . public class ClusterSubscriptionChangedListener implements MessageListener<ClusterNotification> { /** * This method is triggered when a subscription is changed in clustered environment. * * @param message contains the ClusterNotification */ @Override public void onMessage(Message<ClusterNotfication> message) { // message handling logic } } I'm publishing/receiving messages to/from Hazelcast topics from another OSGi bundle. Issue I can publish messages to the topic successfully. But I don't receive the messages from the listener. This is because, when the Hazelcast topic ring buffer runners try to pick the serialized message and de-serialize, it throws a ClassNotFoundException. *And the exception is silently ignored* and the message never received. Root cause Class loader of the Hazelcast bundle cannot see the classes of my bundle. Therefore even though I can publish the message from my bundle, Within Hazelcast it can't de-serialize the ClusterNotification <https://github.com/wso2/andes/blob/v3.1.5/modules/andes-core/broker/src/main/java/org/wso2/andes/server/cluster/coordination/ClusterNotification.java> object since the class loader of Hazelcast bundle cannot see the class. Solution, way forward? 1. After having an offline discussion with Kishanthan we built the hazelcast bundle with <DynamicImport-Package>*</DynamicImport-Package> in the hazelcast pom.xml <https://github.com/hazelcast/hazelcast/blob/v3.6/hazelcast/pom.xml> and we successfully received the messages (We didn't get the ClassNotFoundException). But we need a fix from Hazelcast. 2. Another way Hazelcast has provided is to set the class loader for the HazelcastInstance. So Internally Hazelcast instance will use the provided class loader to deserialize the objects. If we provide our bundle class loader it will properly deserialize the object without an issue. @Kishanthan I tried to set the class loader of the carbon-kernel hazelcast module to the hazelcast instance (when creating the hazelcast instance[2]) and added dynamic imports * property (to get the solution 2 working from the carbon kernel hazelcast module itself). Still I'm having issues in loading the Andes classes thorough the carbon Hazelcast module class loader. [1] https://github.com/hazelcast/hazelcast/issues/8139 [2] https://github.com/wso2/carbon-kernel/blob/hamming-release-poc/modules/carbon-hazelcast/component/src/main/java/org/wso2/carbon/hazelcast/internal/CarbonHazelcastComponent.java#L60 Regards, Asitha -- *Asitha Nanayakkara* Software Engineer WSO2, Inc. http://wso2.com/ Mob: +94 77 853 0682
_______________________________________________ Dev mailing list Dev@wso2.org http://wso2.org/cgi-bin/mailman/listinfo/dev
