Java classpath seems to change after JBoss starts when application creates its own thread

Issue

• Our classpath seems to get corrupted/changed somehow after a while because we are observing a failure to find META-INF/persistence.xml when we attempt to build a RESOURCE_LOCAL EntityManagerFactory via:

    entityManagerFactory = Persistence.createEntityManagerFactory(persistenceUnit); 

We do this well after app server start up and it doesn't always happen. Why would the classpath be different after app server start up? What's going on here?

javax.persistence.PersistenceException: No Persistence provider for EntityManager named example
        at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:69)
        at com.example.server.transaction.ResourceLocalTransactionWrapper.buildEntityManagerFactory(ResourceLocalTransactionWrapper.java:123)
        ...
        at com.example.server.hacluster.HATopologyListenerBase.handleTopologyChange(HATopologyListenerBase.java:242)
        at com.example.server.hacluster.HATopologyListener.topologyChanged(HATopologyListener.java:121)
        at com.example.server.hacluster.HATopologyMonitor$1.run(HATopologyMonitor.java:130)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
        at java.util.concurrent.FutureTask.run(FutureTask.java:166)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:722)