Description of problem: Accessing the 'locks held' attribute of the exo:portal="portal",repository="repository",workspace="system",cache-type=LOCK_CACHE,jmx-resource=MVCCLockManager MBean fails with the following exception WARN [org.jboss.cache.jmx.ResourceDMBean] (RMI TCP Connection(32)-10.5.48.29) Exception while reading value of attribute locks held java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor600.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.jboss.cache.jmx.ResourceDMBean$MethodAttributeEntry.invoke(ResourceDMBean.java:657) at org.jboss.cache.jmx.ResourceDMBean.getNamedAttribute(ResourceDMBean.java:537) at org.jboss.cache.jmx.ResourceDMBean.getAttribute(ResourceDMBean.java:185) at org.jboss.mx.server.RawDynamicInvoker.getAttribute(RawDynamicInvoker.java:117) at org.jboss.mx.server.MBeanServerImpl.getAttribute(MBeanServerImpl.java:565) at sun.reflect.GeneratedMethodAccessor584.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.jboss.jmx.connector.invoker.InvokerAdaptorService.invoke(InvokerAdaptorService.java:266) at sun.reflect.GeneratedMethodAccessor313.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96) at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:138) at org.jboss.mx.server.Invocation.invoke(Invocation.java:90) at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:140) at org.jboss.jmx.connector.invoker.SerializableInterceptor.invoke(SerializableInterceptor.java:74) at org.jboss.jmx.connector.invoker.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:107) at org.jboss.mx.server.Invocation.invoke(Invocation.java:90) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668) at org.jboss.invocation.jrmp.server.JRMPProxyFactory.invoke(JRMPProxyFactory.java:180) at sun.reflect.GeneratedMethodAccessor312.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668) at org.jboss.invocation.jrmp.server.JRMPInvoker$MBeanServerAction.invoke(JRMPInvoker.java:855) at org.jboss.invocation.jrmp.server.JRMPInvoker.invoke(JRMPInvoker.java:422) at sun.reflect.GeneratedMethodAccessor311.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322) at sun.rmi.transport.Transport$1.run(Transport.java:177) at java.security.AccessController.doPrivileged(Native Method) at sun.rmi.transport.Transport.serviceCall(Transport.java:173) at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:553) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:808) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:667) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:679) Caused by: java.lang.NullPointerException at org.jboss.cache.lock.MVCCLockManager.getNumberOfLocksHeld(MVCCLockManager.java:335) ... 49 more How reproducible: always Steps to Reproduce: 1. Use JON to collect metrics from EPP 5.2 - OR - 1. Start EPP 5.2.2 2. Use jmx-console, navigate to exo:portal="portal",repository="repository",workspace="system",cache-type=LOCK_CACHE,jmx-resource=MVCCLockManager MBean Actual results: NullPointerException Expected results: Number of locks held Additional info: On the JBoss Cache side, this NPE is tracked in https://issues.jboss.org/browse/JBCACHE-1627. The question is why is this particular cache instance not started properly.