Site Import Fail with java.lang.NullPointerException

Symptoms

1. A Site Import from Confluence Server or Cloud to Confluence Cloud fails with the error:
   There was an error during import. You may either try again or raise a support request.
2. The following error is logged in the logs:

   2014-12-18 18:12:03.912196500 java.lang.NullPointerException
   2014-12-18 18:12:03.912196500   at com.atlassian.confluence.importexport.xmlimport.FileBackupImporter.getIdBasedAttachmentPathMapping(FileBackupImporter.ja                            va:225)
   2014-12-18 18:12:03.912200500   at com.atlassian.confluence.importexport.xmlimport.FileBackupImporter.importAttachments(FileBackupImporter.java:298)
   2014-12-18 18:12:03.912201500   at com.atlassian.confluence.importexport.xmlimport.FileBackupImporter.importEverything(FileBackupImporter.java:157)
   2014-12-18 18:12:03.912201500   at com.atlassian.confluence.importexport.xmlimport.BackupImporter$1.doInTransactionWithoutResult(BackupImporter.java:259)
   2014-12-18 18:12:03.912203500   at org.springframework.transaction.support.TransactionCallbackWithoutResult.doInTransaction(TransactionCallbackWithoutResul                            t.java:33)
   2014-12-18 18:12:03.912203500   at com.atlassian.confluence.importexport.xmlimport.RestorePluginStateStoreTransactionCallbackDecorator.doInTransaction(Rest                            orePluginStateStoreTransactionCallbackDecorator.java:50)
   2014-12-18 18:12:03.912206500   at com.atlassian.confluence.importexport.xmlimport.RestoreBandanaValuesTransactionCallbackDecorator.doInTransaction(Restore                            BandanaValuesTransactionCallbackDecorator.java:50)
   2014-12-18 18:12:03.912207500   at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:128)
   2014-12-18 18:12:03.912208500   at com.atlassian.confluence.importexport.xmlimport.BackupImporter.doImportInternal(BackupImporter.java:211)
   2014-12-18 18:12:03.912209500   at com.atlassian.confluence.importexport.Importer.doImport(Importer.java:77)
   2014-12-18 18:12:03.912209500   at com.atlassian.confluence.importexport.DefaultImportExportManager.performImportInternal(DefaultImportExportManager.java:8                            3)
   2014-12-18 18:12:03.912216500   at com.atlassian.confluence.importexport.DefaultImportExportManager.performImport(DefaultImportExportManager.java:73)
   2014-12-18 18:12:03.912217500   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   2014-12-18 18:12:03.912217500   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   2014-12-18 18:12:03.912223500   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   2014-12-18 18:12:03.912223500   at java.lang.reflect.Method.invoke(Method.java:597)
   2014-12-18 18:12:03.912224500   at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
   2014-12-18 18:12:03.912224500   at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
   2014-12-18 18:12:03.912225500   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
   2014-12-18 18:12:03.912226500   at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
   2014-12-18 18:12:03.912227500   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
   2014-12-18 18:12:03.912228500   at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
   2014-12-18 18:12:03.912228500   at $Proxy160.performImport(Unknown Source)
   2014-12-18 18:12:03.912229500   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   2014-12-18 18:12:03.912229500   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   2014-12-18 18:12:03.912230500   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   2014-12-18 18:12:03.912232500   at java.lang.reflect.Method.invoke(Method.java:597)
   2014-12-18 18:12:03.912233500   at com.atlassian.plugin.osgi.hostcomponents.impl.DefaultComponentRegistrar$ContextClassLoaderSettingInvocationHandler.invok                            e(DefaultComponentRegistrar.java:134)
   2014-12-18 18:12:03.912233500   at $Proxy447.performImport(Unknown Source)
   2014-12-18 18:12:03.912234500   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   2014-12-18 18:12:03.912235500   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   2014-12-18 18:12:03.912235500   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   2014-12-18 18:12:03.912236500   at java.lang.reflect.Method.invoke(Method.java:597)
   2014-12-18 18:12:03.912236500   at com.atlassian.plugin.osgi.bridge.external.HostComponentFactoryBean$DynamicServiceInvocationHandler.invoke(HostComponentF                            actoryBean.java:154)
   2014-12-18 18:12:03.912237500   at $Proxy447.performImport(Unknown Source)
   2014-12-18 18:12:03.912238500   at com.atlassian.confluence.importexport.actions.ImportLongRunningTask.runInternal(ImportLongRunningTask.java:95)
   2014-12-18 18:12:03.912238500   at com.atlassian.confluence.util.longrunning.ConfluenceAbstractLongRunningTask.run(ConfluenceAbstractLongRunningTask.java:2                            7)
   2014-12-18 18:12:03.912240500   at com.atlassian.ondemand.confluenceimporter.service.importer.OnDemandImportLongRunningTask.runInternal(OnDemandImportLongR                            unningTask.java:182)
   2014-12-18 18:12:03.912243500   at com.atlassian.confluence.util.longrunning.ConfluenceAbstractLongRunningTask.run(ConfluenceAbstractLongRunningTask.java:2                            7)
   2014-12-18 18:12:03.912244500   at com.atlassian.confluence.util.longrunning.ManagedTask.run(ManagedTask.java:58)
   2014-12-18 18:12:03.912244500   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
   2014-12-18 18:12:03.912245500   at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
   2014-12-18 18:12:03.912246500   at java.util.concurrent.FutureTask.run(FutureTask.java:138)
   2014-12-18 18:12:03.912246500   at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
   2014-12-18 18:12:03.912247500   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
   2014-12-18 18:12:03.912247500   at java.lang.Thread.run(Thread.java:662)
   2014-12-18 18:12:03.945779500 2014-12-18 18:12:03,941 INFO [Long running task: Importing data] [confluenceimporter.service.importer.OnDemandImportLongRunni                            ngTask] runInternal Import has finished running. isSuccessful=false, status=Import failed. Check your server logs for more information. null, elapsedTime=8                            992
   

This error does not occur when you restore the backup to a Confluence Server.

More errors may be logged as well:

2015-01-21 14:38:07.298636500 2015-01-21 14:38:07,289 WARN [scheduler_Worker-1] [persistence.hibernate.batch.AbstractBatchProcessor] processBatch batch failed falling back to individual processing
2015-01-21 14:38:07.298639500 java.lang.NullPointerException
2015-01-21 14:38:07.298639500 	at com.atlassian.crowd.embedded.hibernate2.batch.operation.RemoveUserOperation.performOperation(RemoveUserOperation.java:38)
2015-01-21 14:38:07.298640500 	at com.atlassian.crowd.embedded.hibernate2.batch.operation.RemoveUserOperation.performOperation(RemoveUserOperation.java:17)

NB: If you are receiving this error, this is unrelated to this particular failure. Please see CONF-34180.

_"Import failed. Check your server logs for more information. 
com.atlassian.crowd.exception.runtime.GroupNotFoundException: Group <_licensed-confluence> does not exist"_

Cause:
Recent changes to the definition of Attachments as ContentEntityObjects.

Workaround

1. Search for an <object> Attachment containing the following regex: <property.*class="GlobalDescription" (i.e. a <property> tag with class GlobalDescription). Its title should be either global.logo or favicon-XX (there are different favicons). If it's not one of them, please comment on the ticket before removing.
2. Remove the <object> tag (including its children)

NB: Importing into OD-39 or 42 Server releases is successful and may be helpful in working around this problem if attempting to restore a backup from a Cloud instance that has been decommissioned.