[ARTEMIS-1526] ActiveMQServerControl.listConsumers() can fail with NullPointer

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 2.5.0
• Assignee: Unassigned
• Reporter: Pat Fox
• Created: 28/Nov/17 07:44
• Updated: 03/Jan/18 17:06
• Resolved: 03/Jan/18 17:06

Description

race condition between ActiveMQServerControl.listConsumers() and closing client sessions can cause the following NullPointer

java.lang.NullPointerException: null
	at org.apache.activemq.artemis.core.management.impl.view.ConsumerView.toJson(Unknown Source)
	at org.apache.activemq.artemis.core.management.impl.view.ConsumerView.toJson(Unknown Source)
	at org.apache.activemq.artemis.core.management.impl.view.ActiveMQAbstractView.getResultsAsJson(ActiveMQAbstractView.java:68)
	at org.apache.activemq.artemis.core.management.impl.ActiveMQServerControlImpl.listConsumers(ActiveMQServerControlImpl.java:1727)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
	at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:112)
	at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:46)
	at com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:237)
	at com.sun.jmx.mbeanserver.PerInterface.invoke(PerInterface.java:138)

The ActiveMQServerControl.listConsumers() retrieves the associated ServerSession and this may be null if the session has been closed AFTER the listConsumers() has been called but BEFORE the session is retrieved.

Issue Links

• links to: GitHub Pull Request #1675