[ARTEMIS-1670] NPE was found in when dropping durable subscriptions from a topic

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.5.5
• Component/s: Broker
• Assignee: Unassigned
• Reporter: Lin Gao
• Created: 09/Feb/18 06:22
• Updated: 03/Aug/21 13:33
• Resolved: 26/Feb/18 17:03

Description

In WildFly, set up a topic by executing following CLI:

/subsystem=messaging-activemq/server=default:write-attribute(name=security-enabled,value=false)
:reload
/subsystem=messaging-activemq/server=default/jms-topic=testTopic:add(entries=[java:/jms/topic/testTopic, java:jboss/exported/jms/topic/testTopic])

Then create a durable subscriber on it using the following test code:
 

    public static void main(String[] args) throws Exception {
    	Connection connection = null;
        Context namingContext = null;
        try {
            final Properties env = new Properties();
            env.put(Context.INITIAL_CONTEXT_FACTORY, "org.wildfly.naming.client.WildFlyInitialContextFactory");
            env.put(Context.PROVIDER_URL, System.getProperty(Context.PROVIDER_URL, "http-remoting://127.0.0.1:8080"));
            namingContext = new InitialContext(env);
            Topic topic = (Topic) namingContext.lookup("/jms/topic/testTopic");
            ConnectionFactory connectionFactory = (ConnectionFactory) namingContext.lookup("jms/RemoteConnectionFactory");
            connection = connectionFactory.createConnection();
            connection.setClientID("durable-client");
            connection.start();
            Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            MessageProducer messageProducer = session.createProducer(topic);
            TopicSubscriber subscriber = session.createDurableSubscriber(topic, "subscriber-1");
            TextMessage message1 = session.createTextMessage("This is a text message 1");
            messageProducer.send(message1);
            System.out.println("Sent message: " + message1.getText());
            TextMessage messageReceived = (TextMessage) subscriber.receive();
            System.out.println("Received message: " + messageReceived.getText());

            try {
				Thread.sleep(20000); // wait 20 seconds before un-subscribe
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
            subscriber.close();
            session.unsubscribe("subscriber-1");
        } finally {
			if (connection != null) {
				connection.close();
			}
            if (namingContext != null) {
            	namingContext.close();
            }
        }
    }

 
The code above will sleep 20 seconds before un-subscribe, try to execute the following WildFly CLI within 20 seconds:

/subsystem=messaging-activemq/server=default/jms-topic=testTopic:drop-durable-subscription(client-id=durable-client, subscription-name=subscriber-1)

 
The WildFly CLI succeeded, but there is a NPE in the server log:

09:10:42,340 ERROR [org.apache.activemq.artemis.core.server] (Thread-3 (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$3@7ba46694)) AMQ224065: Failed to remove auto-created queue testSubscriberClientIdjmsTopicOperations.testSubscriber: java.lang.NullPointerException
	at org.apache.activemq.artemis.jms.server.impl.JMSServerManagerImpl$JMSQueueDeleter.delete(JMSServerManagerImpl.java:1669) [artemis-jms-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.core.server.impl.AutoCreatedQueueManagerImpl$1.run(AutoCreatedQueueManagerImpl.java:36) [artemis-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.utils.ReferenceCounterUtil.decrement(ReferenceCounterUtil.java:54) [artemis-commons-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.core.server.impl.AutoCreatedQueueManagerImpl.decrement(AutoCreatedQueueManagerImpl.java:58) [artemis-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.core.server.impl.QueueImpl.removeConsumer(QueueImpl.java:786) [artemis-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.core.server.impl.ServerConsumerImpl.removeItself(ServerConsumerImpl.java:496) [artemis-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.core.server.impl.ServerConsumerImpl.close(ServerConsumerImpl.java:443) [artemis-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.core.server.impl.ServerSessionImpl.closeConsumer(ServerSessionImpl.java:1174) [artemis-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.core.protocol.core.ServerSessionPacketHandler.internalHandlePacket(ServerSessionPacketHandler.java:445) [artemis-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.core.protocol.core.ServerSessionPacketHandler.lambda$handlePacket$0(ServerSessionPacketHandler.java:211) [artemis-server-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at org.apache.activemq.artemis.utils.OrderedExecutorFactory$OrderedExecutor$ExecutorTask.run(OrderedExecutorFactory.java:122) [artemis-commons-1.5.5.008-redhat-1.jar:1.5.5.008-redhat-1]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [rt.jar:1.8.0_151]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [rt.jar:1.8.0_151]
	at java.lang.Thread.run(Thread.java:748) [rt.jar:1.8.0_151]

Despite this error, subscription is removed and listing of all subscriptions is now empty. Operation works as expected, however there is an Error logged on server side.

Issue Links

• links to: GitHub Pull Request #1860