[ https://issues.apache.org/jira/browse/WICKET-6639?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Mikhail Fursov updated WICKET-6639: ----------------------------------- Description: Sometimes when I return to my website after some period I see the following exception: {noformat} java.lang.NullPointerException at org.apache.wicket.page.PageStoreManager$SessionEntry.clear(PageStoreManager.java:365) at org.apache.wicket.page.PageStoreManager$SessionEntry.valueUnbound(PageStoreManager.java:353) at org.apache.catalina.session.StandardSession.removeAttributeInternal(StandardSession.java:1784) at org.apache.catalina.session.StandardSession.expire(StandardSession.java:856) at org.apache.catalina.session.StandardSession.isValid(StandardSession.java:659) at org.apache.catalina.session.ManagerBase.processExpires(ManagerBase.java:573) at org.apache.catalina.session.ManagerBase.backgroundProcess(ManagerBase.java:558) at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5496) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1351) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1355) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1355) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1333){noformat} This is very hard to investigate what is the reason for this bug from my side because I do not have a stable reproducer , but I believe one of the following 1-line fixes in Wicket # Adding a null check for sessionCache before using it # Making sessionCache field never null can resolve this problem. was: Sometimes when I return to my website after some period I see the following exception: {noformat} java.lang.NullPointerException at org.apache.wicket.page.PageStoreManager$SessionEntry.clear(PageStoreManager.java:365) at org.apache.wicket.page.PageStoreManager$SessionEntry.valueUnbound(PageStoreManager.java:353) at org.apache.catalina.session.StandardSession.removeAttributeInternal(StandardSession.java:1784) at org.apache.catalina.session.StandardSession.expire(StandardSession.java:856) at org.apache.catalina.session.StandardSession.isValid(StandardSession.java:659) at org.apache.catalina.session.ManagerBase.processExpires(ManagerBase.java:573) at org.apache.catalina.session.ManagerBase.backgroundProcess(ManagerBase.java:558) at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5496) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1351) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1355) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1355) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1333){noformat} This is very hard to investigate what is the reason for this bug from my side because I do not know a stable reproducer , but I believe one of the following 1-line fixes in Wicket # Adding a null check for sessionCache before calling it # Making sessionCache never null can resolve this problem. > PageStoreManager$SessionEntry.clear produces NullPointerException > ----------------------------------------------------------------- > > Key: WICKET-6639 > URL: https://issues.apache.org/jira/browse/WICKET-6639 > Project: Wicket > Issue Type: Bug > Components: wicket > Affects Versions: 8.3.0 > Reporter: Mikhail Fursov > Priority: Major > Original Estimate: 1h > Remaining Estimate: 1h > > Sometimes when I return to my website after some period I see the following > exception: > {noformat} > java.lang.NullPointerException > at > org.apache.wicket.page.PageStoreManager$SessionEntry.clear(PageStoreManager.java:365) > at > org.apache.wicket.page.PageStoreManager$SessionEntry.valueUnbound(PageStoreManager.java:353) > at > org.apache.catalina.session.StandardSession.removeAttributeInternal(StandardSession.java:1784) > at > org.apache.catalina.session.StandardSession.expire(StandardSession.java:856) > at > org.apache.catalina.session.StandardSession.isValid(StandardSession.java:659) > at > org.apache.catalina.session.ManagerBase.processExpires(ManagerBase.java:573) > at > org.apache.catalina.session.ManagerBase.backgroundProcess(ManagerBase.java:558) > at > org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5496) > at > org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1351) > at > org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1355) > at > org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1355) > at > org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1333){noformat} > > This is very hard to investigate what is the reason for this bug from my side > because I do not have a stable reproducer , but I believe one of the > following 1-line fixes in Wicket > # Adding a null check for sessionCache before using it > # Making sessionCache field never null > can resolve this problem. > -- This message was sent by Atlassian JIRA (v7.6.3#76005)