It is possible for the CommitMarkableResource recovery manager to attempt to activate an AtomicAction while it is being committed which can cause filenotfoundstacktrace and NullPointerException

Basically:

1. App thread creates AA
2. AA UID is seen in phase1 recovery thread by CommitMarkableResourceRecoveryModule
3. App thread commits AA
4. App thread deletes AA UID
5. Recovery thread tries to activate AA with UID in CommitMarkableResourceRecoveryModule but it gets exceptions as shown here:
12:23:07 �[0m�[33m12:23:07,915 WARN [com.arjuna.ats.arjuna] (Periodic Recovery) Could not query objectstore: : java.io.IOException: java.lang.NullPointerException
12:23:07 at com.arjuna.ats.arjuna.StateManager.unpackHeader(StateManager.java:732) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
12:23:07 at com.arjuna.ats.internal.jta.recovery.arjunacore.RecoverConnectableAtomicAction.<init>(RecoverConnectableAtomicAction.java:52) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
12:23:07 at com.arjuna.ats.internal.jta.recovery.arjunacore.CommitMarkableResourceRecordRecoveryModule.periodicWorkFirstPass(CommitMarkableResourceRecordRecoveryModule.java:379) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
12:23:07 at com.arjuna.ats.internal.arjuna.recovery.PeriodicRecovery.doWorkInternal(PeriodicRecovery.java:743) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
12:23:07 at com.arjuna.ats.internal.arjuna.recovery.PeriodicRecovery.run(PeriodicRecovery.java:371) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
12:23:07 Caused by: java.lang.NullPointerException
12:23:07 at com.arjuna.ats.arjuna.StateManager.unpackHeader(StateManager.java:697) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
12:23:07 ... 4 more
12:23:07
15:16:36 �[0m�[33m15:16:36,247 WARN [com.arjuna.ats.arjuna] (Periodic Recovery) Could not query objectstore: : com.arjuna.ats.arjuna.exceptions.ObjectStoreException: ShadowingStore::read_state error: java.io.FileNotFoundException: /tmp/activemq-soak/ibm-mq-testsuite/src/test/config/activemq/install/target/jboss-eap/standalone/data/tx-object-store/ShadowNoFileLockStore/defaultStore/StateManager/BasicAction/TwoPhaseCoordinator/AtomicAction/0_ffff0a106418_-2b02421b_534ffd61_4c1764 (No such file or directory)
15:16:36 at com.arjuna.ats.internal.arjuna.objectstore.ShadowingStore.read_state(ShadowingStore.java:412) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
15:16:36 at com.arjuna.ats.internal.arjuna.objectstore.FileSystemStore.read_committed(FileSystemStore.java:98) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
15:16:36 at com.arjuna.ats.internal.jta.recovery.arjunacore.RecoverConnectableAtomicAction.<init>(RecoverConnectableAtomicAction.java:48) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
15:16:36 at com.arjuna.ats.internal.jta.recovery.arjunacore.CommitMarkableResourceRecordRecoveryModule.periodicWorkFirstPass(CommitMarkableResourceRecordRecoveryModule.java:379) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
15:16:36 at com.arjuna.ats.internal.arjuna.recovery.PeriodicRecovery.doWorkInternal(PeriodicRecovery.java:743) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
15:16:36 at com.arjuna.ats.internal.arjuna.recovery.PeriodicRecovery.run(PeriodicRecovery.java:371) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
15:16:36 Caused by: java.io.FileNotFoundException: /tmp/activemq-soak/ibm-mq-testsuite/src/test/config/activemq/install/target/jboss-eap/standalone/data/tx-object-store/ShadowNoFileLockStore/defaultStore/StateManager/BasicAction/TwoPhaseCoordinator/AtomicAction/0_ffff0a106418_-2b02421b_534ffd61_4c1764 (No such file or directory)
15:16:36 at java.io.FileInputStream.open(Native Method) [rt.jar:1.7.0_51]
15:16:36 at java.io.FileInputStream.<init>(FileInputStream.java:146) [rt.jar:1.7.0_51]
15:16:36 at com.arjuna.ats.internal.arjuna.objectstore.ShadowingStore.read_state(ShadowingStore.java:406) [jbossjts-jacorb-4.17.18.Final-redhat-1.jar:4.17.18.Final-redhat-1]
15:16:36 ... 5 more
15:16:36