Description of problem:
Attempting to invoke the "Force Major Column Family Compaction" operation on a ColumnFamily fails and the operation error message is as follows:

    org.mc4j.ems.connection.EmsInvocationException: Exception on invocation of [forceTableCompaction]javax.management.RuntimeMBeanException: java.lang.NullPointerException
        at org.mc4j.ems.impl.jmx.connection.bean.operation.DOperation.invoke(DOperation.java:126)
        at org.rhq.plugins.cassandra.util.KeyspaceService.compact(KeyspaceService.java:96)
        at org.rhq.plugins.cassandra.KeyspaceComponent.compactKeyspace(KeyspaceComponent.java:168)
        at org.rhq.plugins.cassandra.ColumnFamilyComponent.invokeOperation(ColumnFamilyComponent.java:71)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.rhq.core.pc.inventory.ResourceContainer$ComponentInvocation.call(ResourceContainer.java:654)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:744)
    Caused by: javax.management.RuntimeMBeanException: java.lang.NullPointerException
        at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.rethrow(DefaultMBeanServerInterceptor.java:839)
        at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.rethrowMaybeMBeanException(DefaultMBeanServerInterceptor.java:852)
        at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:821)
        at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
        at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1487)
        at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:97)
        at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1328)
        at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1420)
        at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:848)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322)
        at sun.rmi.transport.Transport$1.run(Transport.java:177)
        at sun.rmi.transport.Transport$1.run(Transport.java:174)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:556)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:811)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:670)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:744)
        at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:275)
        at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:252)
        at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:161)
        at javax.management.remote.rmi.RMIConnectionImpl_Stub.invoke(Unknown Source)
        at javax.management.remote.rmi.RMIConnector$RemoteMBeanServerConnection.invoke(RMIConnector.java:1029)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.mc4j.ems.impl.jmx.connection.support.providers.proxy.JMXRemotingMBeanServerProxy.invoke(JMXRemotingMBeanServerProxy.java:59)
        at com.sun.proxy.$Proxy54.invoke(Unknown Source)
        at org.mc4j.ems.impl.jmx.connection.bean.operation.DOperation.invoke(DOperation.java:110)
        ... 12 more
    Caused by: java.lang.NullPointerException
        at org.apache.cassandra.service.StorageService.getValidColumnFamilies(StorageService.java:2292)
        at org.apache.cassandra.service.StorageService.forceTableCompaction(StorageService.java:2166)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:75)
        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:279)
        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)
        at com.sun.jmx.mbeanserver.MBeanSupport.invoke(MBeanSupport.java:252)
        at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
        at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
        at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1487)
        at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:97)
        at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1328)
        at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1420)
        at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:848)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322)
        at sun.rmi.transport.Transport$1.run(Transport.java:177)
        at sun.rmi.transport.Transport$1.run(Transport.java:174)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:556)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:811)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:670)
        ... 3 more
 
There is no real message written to the agent log other then:

    INFO  [ResourceContainer.invoker.nonDaemon-40] (org.rhq.plugins.cassandra.KeyspaceComponent)- Executing compaction on  keyspace [rhq]

Version-Release number of selected component (if applicable):
3.2.0.GA

How reproducible:
Always

Steps to Reproduce:
1. Install and start JBoss ON 3.2 system
2. After storage node is in inventory and reported as available, invoke the _Force Major Column Family Compaction_ operation on RHQ Storage Nodes / RHQ Storage Node(...) / Keyspaces / rhq / ColomnFamilies / raw_metrics

Actual results:
Compaction does not execute and operation status reports FAILURE with the exception and stack mentioned above.

Expected results:
Compaction operation runs as normal and operation status reports SUCCESS. Compaction is actually performed and rhq-storage.log reports something similar to:

    INFO [CompactionExecutor:76] 2014-07-09 18:33:17,065 CompactionTask.java (line 262) Compacted 2 sstables to [../../../rhq-data/data/rhq/raw_metrics/rhq-raw_metrics-ic-8,].  61,562,262 bytes to 51,079,953 (~82% of original) in 9,727ms = 5.008085MB/s.  5,943 total rows, 2,984 unique.  Row merge counts were {1:25, 2:2959, }