NullPointerException during space import due to cache management
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*Except Fisheye and Crucible
Summary
The Space import procedure throws a java.lang.NullPointerException on the UI, no further details are showed.
Diagnosis
Looking for references at the atlassian-confluence.log, the following stack is present during Space import:
com.atlassian.confluence.importexport.ImportExportException: java.lang.NullPointerException
-- url: /admin/restore.action | referer: http://localhost:8080/admin/backup.action | traceId: 9fd02f1661b206f0 | userName: test | action: restore
2021-03-18 17:19:18,829 ERROR [Long running task: Importing data] [confluence.importexport.actions.ImportLongRunningTask] runInternal Failure during import2021-03-18 17:19:18,815 ERROR [Long running task: Importing data] [confluence.importexport.xmlimport.BackupImporter] importEntities Cannot import the entities:
-- url: /admin/restore.action | referer: http://localhost:8080/admin/backup.action | traceId: 9fd02f1661b206f0 | userName: test | action: restore
java.lang.NullPointerException
at com.atlassian.cache.hazelcast.HazelcastHybridCache.isFlushable(HazelcastHybridCache.java:311)
at com.atlassian.cache.impl.AbstractCacheManager.flushCaches(AbstractCacheManager.java:103)
...
Caused by: java.lang.NullPointerException
at com.atlassian.cache.hazelcast.HazelcastHybridCache.isFlushable(HazelcastHybridCache.java:311)
at com.atlassian.cache.impl.AbstractCacheManager.flushCaches(AbstractCacheManager.java:103)
at com.atlassian.confluence.cache.hazelcast.ConfluenceHazelcastCacheManager.flushCaches(ConfluenceHazelcastCacheManager.java:93)
at com.atlassian.confluence.impl.cache.hibernate.HibernateClusterAwareCacheManager.flushCaches(HibernateClusterAwareCacheManager.java:91)
at java.base/java.util.ArrayList.forEach(Unknown Source)
at com.atlassian.confluence.impl.cache.CacheFlusher.lambda$createCompositeCacheFlusher$0(CacheFlusher.java:37)
at com.atlassian.confluence.importexport.xmlimport.BackupImporter.postProcess(BackupImporter.java:466)
at com.atlassian.confluence.importexport.xmlimport.BackupImporter.importEntities(BackupImporter.java:402)
... 38 moreIf you find this stack trace, it is very likely that when you try to flush cache or access the Cache Statistics page, you observe the following errors:
- Flush the cache on the Confluence node first via the REST API endpoint will fail with HTTP status code 500 Internal Server Error:
curl -u <adminUsername>:<adminPassword> -X DELETE "http://CONFLUENCE_URL/rest/cacheManagement/1.0/cacheEntries"- Trying to access the Cache Statistic page it throws "Fetch of cache statistics failed":
http://CONFLUENCE_URL/admin/cache/showStatistics.action
Cause
We are hitting into this issue of java.lang.NullPointerException due to cache management. This appears to be caused by corrupted caches on the affected Confluence node.
Solution
Please, follow the steps below to address the issue:
- Stop the Confluence node where the space import is failing
- Follow the steps in KB How to clear Confluence plugins cache on this specific Confluence node
- Restart the Confluence node and try the Space Import again