javax.ejb.EJBException: Could not passivate; failed to save state
     at org.jboss.ejb3.cache.simple.StatefulSessionFilePersistenceManager.passivateSession(StatefulSessionFilePersistenceManager.java:406)
     at org.jboss.ejb3.cache.simple.SimpleStatefulCache.passivate(SimpleStatefulCache.java:301)
     at org.jboss.ejb3.cache.simple.SimpleStatefulCache$SessionTimeoutTask.run(SimpleStatefulCache.java:209)
Caused by: java.io.IOException
     at org.jboss.serial.persister.RegularObjectPersister.writeSlotWithMethod(RegularObjectPersister.java:129)
     at org.jboss.serial.persister.RegularObjectPersister.defaultWrite(RegularObjectPersister.java:86)
     at org.jboss.serial.persister.RegularObjectPersister.writeData(RegularObjectPersister.java:62)
     at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.describeObject(ObjectDescriptorFactory.java:276)
     at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectOutput.writeObject(DataContainer.java:206)
     at org.jboss.serial.persister.RegularObjectPersister.writeSlotWithFields(RegularObjectPersister.java:182)
     at org.jboss.serial.persister.RegularObjectPersister.defaultWrite(RegularObjectPersister.java:90)
     at org.jboss.serial.persister.RegularObjectPersister.writeData(RegularObjectPersister.java:62)
     at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.describeObject(ObjectDescriptorFactory.java:276)
     at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectOutput.writeObject(DataContainer.java:206)
     at org.jboss.serial.persister.RegularObjectPersister.writeSlotWithFields(RegularObjectPersister.java:182)
     at org.jboss.serial.persister.RegularObjectPersister.defaultWrite(RegularObjectPersister.java:90)
     at org.jboss.serial.persister.RegularObjectPersister.writeData(RegularObjectPersister.java:62)
     at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.describeObject(ObjectDescriptorFactory.java:276)
     at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectOutput.writeObject(DataContainer.java:206)
     at org.jboss.serial.persister.ArrayPersister.saveObjectArray(ArrayPersister.java:110)
     at org.jboss.serial.persister.ArrayPersister.writeData(ArrayPersister.java:101)
     at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.describeObject(ObjectDescriptorFactory.java:276)
     at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectOutput.writeObject(DataContainer.java:206)
     at org.jboss.serial.io.JBossObjectOutputStream.writeObjectOverride(JBossObjectOutputStream.java:181)
     at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:322)
     at org.jboss.serial.io.MarshalledObject.<init>(MarshalledObject.java:51)
     at org.jboss.ejb3.stateful.StatefulBeanContext.writeExternal(StatefulBeanContext.java:857)
     at org.jboss.serial.persister.ExternalizePersister.writeData(ExternalizePersister.java:58)
     at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.describeObject(ObjectDescriptorFactory.java:276)
     at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectOutput.writeObject(DataContainer.java:206)
     at org.jboss.serial.io.JBossObjectOutputStream.writeObjectOverride(JBossObjectOutputStream.java:181)
     at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:322)
     at org.jboss.ejb3.cache.simple.StatefulSessionFilePersistenceManager.passivateSession(StatefulSessionFilePersistenceManager.java:390)
     ... 2 more
Caused by: java.lang.reflect.InvocationTargetException
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:597)
     at org.jboss.serial.persister.RegularObjectPersister.writeSlotWithMethod(RegularObjectPersister.java:120)
     ... 30 more
Caused by: java.lang.NullPointerException
     at javax.faces.component.UIComponentBase.saveAttachedState(UIComponentBase.java:1364)
     at javax.faces.component.UIComponentBase.saveBindingsState(UIComponentBase.java:1472)
     at javax.faces.component.UIComponentBase.saveState(UIComponentBase.java:1261)
     at javax.faces.component.html.HtmlPanelGroup.saveState(HtmlPanelGroup.java:170)
     at javax.faces.component.UIComponentBase$AttributesMap.writeObject(UIComponentBase.java:1819)
     ... 35 more