java.lang.NullPointerException: null

Help / Discuss
#1

Hello, we are getting NullPointerException error and need help to understand:
We have a XWiki page with a .PDF attachment called “如何创建页面模板-荣芯.pdf” and this .
PDF file is linked with text “如何创建页面模板(荣芯版)” on the page (source code: [[如何创建页面模板(荣芯版>>attach:如何创建页面模板-荣芯.pdf]]).
When clicking on the text with the link, it gives the following error message,
however this used to work just like any other linked attachment, we don’t understand how and why this occurs.
Has anyone experienced the same? Please help and share your experience. Thank you in advance!

2023-11-20 14:14:15,773 [http-nio-8080-exec-42 - http://********************* WARN c.x.x.w.XWikiAction - Uncaught exception: Error number 0 in 11: Uncaught exception
com.xpn.xwiki.XWikiException: Error number 0 in 11: Uncaught exception
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:662)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:339)
at com.xpn.xwiki.web.LegacyActionServlet.service(LegacyActionServlet.java:114)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:623)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:209)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:122)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.xwiki.wysiwyg.filter.ConversionFilter.doFilter(ConversionFilter.java:61)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.xwiki.container.servlet.filters.internal.SetHTTPHeaderFilter.doFilter(SetHTTPHeaderFilter.java:63)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.xwiki.resource.servlet.RoutingFilter.doFilter(RoutingFilter.java:132)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:481)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:673)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:390)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:926)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1791)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.lang.NullPointerException: null
at org.xwiki.attachment.internal.DefaultAttachmentsManager.lambda$getRedirection$0(DefaultAttachmentsManager.java:83)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:176)
at java.base/java.util.Spliterators$IteratorSpliterator.tryAdvance(Spliterators.java:1812)
at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:127)
at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:502)
at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:488)
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.base/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:543)
at org.xwiki.attachment.internal.DefaultAttachmentsManager.getRedirection(DefaultAttachmentsManager.java:85)
at org.xwiki.attachment.internal.AttachmentsRedirectionFilter.redirect(AttachmentsRedirectionFilter.java:67)
at com.xpn.xwiki.web.XWikiAction.handleRedirect(XWikiAction.java:1287)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:629)
… 43 common frames omitted
#2

Thanks for the report. I believe we have a bug.

I think there’s a bug at https://github.com/xwiki/xwiki-platform/blob/03d67d2a96af8d986d7bdec3a70d4e53255d66d1/xwiki-platform-core/xwiki-platform-attachment/xwiki-platform-attachment-api/src/main/java/org/xwiki/attachment/internal/DefaultAttachmentsManager.java#L82

It’s possible in XWiki that getXObjects returns null entries and the code fails to check it.

We’re fixing it. Sorry about that.

To work around the problem, edit the xobjects of that page and make sure you don’t have empty holes in the xobjects.

#3

You can follow the progress at Loading...

#4

You cannot really do that since you cannot choose the index of xobject in the UI, unfortunately.

#5

Are you sure you cannot delete all the xobjects and recreate them all?

EDIT: It should work if you do that and restart xwiki after having deleted the xobjects and before recreating them.

#6

Thanks everyone for all the inputs, appreciate the quick response and your plan to fix the bug.
We were not able to follow the instruction to “edit the xobjects of that page and make sure you don’t have empty holes in the xobjects”, however we resolved it via creating a new page and copying the contents of the existing one.

Thanks again!

1 Like