NullPointerException in PageSubscriptionImpl$CursorIterator.remove(PageSubscriptionImpl.java:1445) in JBoss EAP 6

Issue

• We see this null pointer exception when the JBoss EAP 6 server is under heavy load

ERROR [org.hornetq.core.server] ... HQ224041: Failed to deliver: java.lang.NullPointerException
    at org.hornetq.core.paging.cursor.impl.PageSubscriptionImpl$CursorIterator.remove(PageSubscriptionImpl.java:1445)
    at org.hornetq.core.server.impl.QueueImpl.depage(QueueImpl.java:2214)
    at org.hornetq.core.server.impl.QueueImpl.access$1400(QueueImpl.java:92)
    at org.hornetq.core.server.impl.QueueImpl$DepageRunner.run(QueueImpl.java:2929)
    at org.hornetq.utils.OrderedExecutorFactory$OrderedExecutor$1.run(OrderedExecutorFactory.java:105)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)